Undefined function on COM type library load - SYSTEM:UNSIGNED-INTEGER-TO-64BIT

When loading a COM type library as part of a system:

  (defsystem my-system () :members (("~/mytypes.tlb" :type
  :midl-type-library-file)))

I get the following error:

  The following function is undefined:
  SYSTEM:UNSIGNED-INTEGER-TO-64BIT which is refernced by |COM Member :
  etc...

It seems that this is related to the use of ULONGLONG types in the idl
definitions.

Is this something that should work?  Anyone have any experience of this?

- Dominic