Gloucester full-back Olly Morgan, Leicester duo George Chuter and Ben Kay and Wasps flanker Tom Rees - who has yet to play this season - all drop to the second-string Saxons squad.
Ashton - officially a member of the Saxons party - is promoted as the 32nd member of the elite squad, which is missing several other players through injury.
Veteran Wasps prop Phil Vickery (Wasps) will not return until March at the earliest after a shoulder injury operation.
But England manager Martin Johnson will delay a decision on whether he needs to replace fellow props Andrew Sheridan - out until at least March with a shoulder injury - and Julian White, expected back at the end of the month, in the elite squad until 25 January.
Gloucester centre Mike Tindall and Wasps flanker Joe Worsley are also omitted pending updates on their injuries, although Leicester scrum-half Harry Ellis is retained despite a knee injury preventing him playing for his club in recent months.
Ashton, 22, has scored nine tries in 10 Premiership matches this season and 15 from 16 games in all competitions.
Ashton (left) is in his third season of rugby union, Hape (right) his second
In his first season in rugby union after arriving from Wigan, he scored a record 41 tries - 39 in the league - in only 31 games as Saints won promotion from National League One.
Last season he struggled to adapt initially to the greater demands of the Premiership, with only one try, although still finished top-scorer in the European Challenge Cup among a total of 11 from 18 matches.
But his exploits this term give him a staggering tally of 67 tries in 62 matches in his union career to date.
Hape, who won 14 rugby league caps for New Zealand and scored 83 tries in 131 games for Bradford Bulls before joining Bath in the summer of 2008, qualifies for England on residency grounds.
He joins Flutey and Dylan Hartley as the third New Zealand-born player in the squad, and could follow in the footsteps of fellow ex-Kiwi rugby league internationals Henry Paul and Lesley Vainikolo, who both played for England.
ENGLAND'S CROSS-CODE CONVERTS
Jason Robinson (2001-07) 56 caps, 30 tries
Henry Paul (2002-2004) 6 caps, 6 pts
Andy Farrell (2007) 8 caps, 1 try
Lesley Vainikolo (2008) 5 caps, 0 pts
Hape, 28, has featured largely at inside centre for Bath but will come into contention at outside centre for England, who may use his extra power ahead of Dan Hipkiss or Mathew Tait, in the absence of Tindall.
"He is very strong defensively, he makes very few errors there, and in attack he can offload, go through tackles and win those collisions," manager Martin Johnson told BBC 5 live.
"He is one of those guys who seem to have time on the ball, he is a very smart footballer and it is an opportunity for him to make another step up."
Ashton and Hape could both provide extra firepower to a side that mustered only one try in three autumn Tests against Australia, Argentina and New Zealand.
Foden, capped just once as a replacement scrum-half against Italy in last year's Six Nations, will also offer extra creativity from deep, though Armitage is likely to reclaim the full-back jersey.
Lawes, who won his first and only cap to date as a replacement against Australia in November, replaces Kay in the elite squad.
But his Saints team-mate Shane Geraghty, promoted during the autumn, has to settle for place in the Saxons, who play Ireland A on 31 January and Italy A on 7 February.
He is joined there by three other stand-offs - Danny Cipriani, the in-form Charlie Hodgson, and his Saints team-mate Stephen Myler.
Leicester tight-head Dan Cole, tipped for possible promotion to the senior party, is also included in the Saxons squad, pending a decision on his Tigers team-mate White.
England start their 2010 Six Nations campaign at home to Wales on Saturday 6 February.
England elite player squad:
Forwards (17): T Payne (Wasps), A Sheridan (Sale), J White (Leicester), D Wilson (Bath), D Hartley (Northampton), L Mears (Bath), S Thompson (Brive); S Borthwick (Saracens), L Deacon (Leicester), C Lawes (Northampton), S Shaw (Wasps); S Armitage (London Irish), J Crane (Leicester), T Croft (Leicester), N Easter (Harlequins), J Haskell (Stade Francais), L Moody (Leicester).
Backs (15): D Armitage (London Irish), B Foden (Northampton); C Ashton (Northampton - *injury replacement), M Banahan (Bath), M Cueto (Sale), U Monye (Harlequins); R Flutey (Brive), S Hape (Bath), D Hipkiss (Leicester), M Tait (Sale); T Flood (Leicester), J Wilkinson (Toulon); D Care (Harlequins), H Ellis (Leicester), P Hodgson (London Irish).
* Chris Ashton (Northampton) added to squad from Saxons as injury replacement for Phil Vickery (Wasps)
England Saxons squad:
Forwards: D Bell (Bath), D Cole (Leicester), A Corbisiero (London Irish), M Mullan (Worcester), N Wood (Gloucester); G Chuter (Leicester), D Paice (London Irish), R Webber (Wasps); D Attwood (Gloucester), B Kay (Leicester), N Kennedy (London Irish); P Dowson (Northampton), T Rees (Wasps), C Robshaw (Harlequins), A Saull (Saracens), G Skivington (Wasps), D Ward-Smith (Wasps), B Woods (Leicester).
Backs: O Morgan (Gloucester), C Ashton (Northampton), P Sackey (Wasps), D Strettle (Harlequins), B Barritt (Saracens), S Geraghty (Northampton), D Waldouck (Wasps); D Cipriani (Wasps), C Hodgson (Sale), S Myler, (Northampton); J Simpson (Wasps), R Wigglesworth (Sale), M Young (Newcastle), * B Youngs (Leicester) - injury replacement for J Simpson (Wasps).
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