rebuilding a 32-bit Outlook add-in as 64-bit

I have a Outlook plug-in which is compatible with 32-bit versions of Outlook (2003, 2007 and 2010). But when installed on a 64-bit Outlook 2010, it goes into the inactive add-ins list and is disabled. So I am trying to build the same plug-in as a 64-bit application so that it works with the 64-bit version of Outlook 2010. But when I try to compile it in 64-bit configuration, I get this error -

fatal error C1905: Front end and back end not compatible (must target same processor).

Can anyone tell me what I must do to compile it successfully?

I am using Visual Studio 2005 Pro on a 64-bit Windows XP OS.

OK. I replaced the x86 compatible lib with a x64 one and now fatal error C1905 has disappeared. But another problem with compiling 64 bit code has popped up. I am getting warnings now suggesting that the functions I had exported to perform custom actions are not found in the dll. Here is the warning message -

WARNING: Entry point 'function name' not found in module 'output dll path' for custom action 'action name'.

There are four such warnings. I am clueless since the same setting worked fine with the 32 bit configuration.

So now build is successful, but the installation still fails. :(

Please help... thanks in advance.

It may be because your path to linked libraries includes x86 libraries instead of x64. Maybe this can help: http://social.msdn.microsoft.com/Forums/en-US/vcgeneral/thread/c19aea98-9b30-4aaa-b417-596eccb05066/