The minister revealed on Thursday that the Welsh Joint Education Committee (WJEC) - the only organisation to tender for the work - would be given control to set up the qualification in Wales.
Ms Davidson said the WJEC's plans were an "exciting and innovative model" and the organisation would now be given £600,000 to develop the project in the current financial year.
But a former senior executive of the International Baccalaureate Organisation (IBO) has criticised the proposed qualification in its current form.
Colin Jenkins, who was director of IBO examinations, is warning against basing the "Welsh Bac" on a mix of the heavily criticised AS level system and A-levels.
The Welsh Assembly Education Minister Jane Davidson has said the new exam will be built on the blocks of AS-levels, A-levels, Vocational A-levels, Key Skills and GNVQs.
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I do not think it will succeed, in my opinion, in its present form
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Colin Jenkins, former IBO exam director
Ministers in London are reviewing the introduction of the AS-level last autumn following criticism.
Mr Jenkins told BBC News Online Wales that the vision of the baccalaureate as a unique Welsh qualification had been "heavily diluted".
"I think its chances of success depend entirely on the scheme reversing a little bit down the road.
International Baccalaureate
"I do not think it will succeed, in my opinion, in its present form," added Mr Jenkins, a former principal of Atlantic College, in south Wales, where the IB has been taught for 30 years.
"I predict disaster. We have kids doing AS and A-levels, which they are already saying is too much, and the current Welsh Bac formula takes on even more."
Mr Jenkins spent seven years jointly researching the Welsh Bac for a report just published by the Institute of Welsh Affairs.
He said the support and advice role of the IBO would have meant tailoring the Welsh Bac to the needs of students.
Ms Davidson said the WJEC would be consulting Professor Jeff Thompson, the IBO's director of international education.
Mr Jenkins said he hoped Professor Thompson would bring his considerable experience to bear but added the IBO's current involvement did not go far enough.
Professor Thompson said the IBO was "positive and supportive" about the notion of the Welsh Bac and in participating in shaping the new qualification into a new version of the IB.
He urged full consultation from all parties to make the qualification a first class package for students in Wales.
Thirteen schools in Wales will be taking part in the pilot project.
The international baccalaureate is based on a core of six subjects - a mix of sciences, maths, a foreign language and humanities subject - and is said to be popular with universities.
Atlantic College at St Donats is one of four schools and colleges in Wales currently teaching the IB.
A pilot scheme at Whitchurch High School in Cardiff began last autumn and the IB is also taught at Swansea College and Llandrillo College, near Colwyn Bay, north Wales.
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The full breadth of education is maintained up to the age of 18 and, in general, universities like that very much
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Gareth Rees, Director of studies, Atlantic College
Atlantic College's director of studies Gareth Rees said a Welsh Bac would be a huge advantage for Welsh students over English sixth formers when applying for a place at university.
Atlantic College's 330 students are drawn from countries all over the world.
"The full breadth of education is maintained up to the age of 18 and in general, universities like that very much," said Mr Rees.
"Emotionally, as a Welshman, I love the idea of a Welsh baccalaureate and were it to become the gold standard for secondary schools in Wales, I would be glad.
"The poor experience of the AS-level over the past year means the time is ripe for the baccalaureate in Wales, " Mr Rees added.