No, the engine runs in 32-bit at this time, and cannot load 64-bit DLLs. We are tracking this possible enhancement in some future release under 1-76ILO.
That is really unfortunate. We absolutely need this feature. The decision about purchase of InstallShield 2011 by our corp is NEGATIVE because of the lack of this feature alone.
Sorry to hear it. We are experimenting with possible ways to implement this, but thunking and marshaling between 32-bit and 64-bit processes is difficult to do for arbitrary variable types. If you could share more about what sort of interaction you need with your .dll, it might help us prioritize aspects of this marshaling layer.
In the meantime, if you need very little code interaction, can you use LaunchApplication with RunDll32 (note you'll probably have to Disable(WOW64FSREDIRECTION) in order to get the 64-bit version of RunDll32) to "launch" your .dll, or some other custom exe wrapper for your .dll?
