Hey Vamp_davis,
Thanks for the link, but trying to keep with in the scope of the cloud licenced software.
The main reason for needing to keep to the 4.6 version is the custom flex/air settings with in an actionscript mobile projects.
Having read up the only way to use a custom one is to add the custom flex/air into the root folder for the flex in the flash builder program files, but that would mean all projects would have to use this which is not so flexible. 
Geoff