Cubase LE5 OEM Lexicon Alpha can't find VST plugins

Hi guys!
I bought a Lexicon Alpha soundboard with Cubase LE5 OEM.
I installed Cubase and Alpha driver and it seems to work with its native vst plugins.

Now, if I try to install additional vst plugins, CB can’t find them.
If I copy the .dll files into program files (x86)\steinberg\Cubase LE5\VSTPlugins or program files (x86)\common files\steinberg\VST2, Cubase doesn’t find the plugins.
I’ve also edited vst 2.x Plug-in Paths and clicked “update” but it doesn’t work.

Does Cubase LE OEM versions support third party plugins?
Does it support windows 7 x64?

I hope you can help me and I thank you in advance for that.

I have the same issue. I bought the same package.
I’ve installed EZ Drummer 2 and the TAL plugins, tried several locations for the dll files, added and updated the path without success. Any idea ?