Hi, I'm currently studding Cert3 Carpentry in Australia and have been looking into the verification procedures to prove i'm a carpenter at the end of the course. As with most things to do with migration there is a lack of detail in any of the information online, so I would recommend talking to a training provider, the TRA or migration agent. (which i'm yet to do!)
But from what i can work out, with no prior Carpentry work, the process is like this: Study a 2 year course in Carpentry as an International Student, included in this you need to do 360 hours (2 days per week, for 6 months) of work experience (as far as i can tell it can be paid or voluntary). After this you need to do the TRA Job Ready Program (this is a new thing they brought in to stop people doing easy courses to get PR*), The First step of this is the Provisional Work Experience (which you did along side the course), then you move onto a Graduate Skills Visa, and complete a full years paid employment, with the TRA monitoring your work, at the end of that they should provide a Positive Skills Assesment, which is the proof DIAC require for a Skilled Migration Pathway.
I'm not entirely sure about this info, but it's my interpretation at the moment!
*"The Job Ready Program will be in effect from 1 January 2010, and will affect people who are resident in Australia and who wish to obtain a skills assessment for a permanent visa. The main group of people affected will be international students completing vocational qualifications in Australia and who wish to apply for General Skilled Migration."
Links:
http://www.deewr.gov.au/Skills/Programs/SkillsAssess/TRA/residenceVisa/JobReady/Pages/Overview.aspx
http://www.gettingdownunder.com/tra-job-ready-program-further-details-released/
Hope this helps?
Alan