Using VLC 0.8.6 plugin in Portable Firefox

I get the plugin working in normal Firefox 1.5 / 2 by copying npvlc.dll, libvlc.dll and part of the plugins from /vlc/plugins to the Firefox/Plugins map.

However both Portable Firefox and Mobile Firefox crash when the plugin is initialized. Portable Firefox 2 for some reason doesn't crash, but it won't react to any play() commands I give it either.
When bypassing the mobile/portable part by not using the loader, but directly using firefoxportable/App/firefox/firefox.exe (in PortableFirefox2) it works.

I submitted a bugreport about this at the VLC website, since the problem started in VLC 0.8.6-test2. Unlike some other bugs I posted, they havn't reacted yet on this one. ( https://trac.videolan.org/vlc/ticket/900 )
So I hoped someone here might know what's causing this...

Has anyone any idea what might cause the crash?

Does anyone know of a solution?