Acrobat plugin Build with SDK6 not Showing in Acrobat X and XI

I'm working on an old Plugin build for Acrobat (not reader) using SDK v6.

This plugin worked fine, upto Acobat 9. (it is only used in Windows)

Now some users tell me it is not showing in Acrobat X.

So I installed a trial verison of Acrobat XI.

After reading some threads, I removed all the references to ADM.

Recompiled it (VisualStudio 2010), and put the debug version in the PLUG-INS folder of Acrobat

But there in no Menu added...

In the General System Information, it is listed under Installed Plug-ins.

But when running in VisualStudio, none of the callbacks is hit. (this worked fine when I was using Acrobat9)

Some of my users are using the plugin in Acrobat7 so I prefer still using SDK6.

Are there any other things that could be incompatible.

What is the first Callback that Acrobat uses to talk to the Plugin.

Can Acrobat give me any info on what is wrong with my Plugin.

Johan