I read somewhere that Microsoft plans to drop support for VBA/VBE in office
apps in future releases of office for 64 bit OS. Remembering how fast the
uptake of 16 to 32 bit systems was, I figure it won't be long that most
office workstations will be 64 bit OS, so I decided to learn about VSTO.

One of the first things I learned was that you can't create UDFs in VSTO -
you have to use VBA (while VBA can interact with VSTO objects, you still need
VBA).

So, the missing piece of info I have not been able to track down is how we
will be able to create UDF's in excel for environments where VBA is no longer
supported. Perhaps I have misundestood something I read?