I did that already, but that failed as explained.
I did get the JaExtensions Manager to work, and while I had some difficulty and had to manually make some directories in the repository path, I got the files in the repository, and then the updates worked. (I have the T3 framework, the T3 plugin and the purity iii template all happy now in jaextension manager)
Had similar, but slightly different issues on 2 different sites.
Greg