Visual Studio 2008 & Intellisense problems

I'm working on a solution where a source file soulfu.c, is used by two different projects. The least significant project defines the _SOULFU_LIB preprocessor definition, while the most significant project does not. When soulfu.c is edited, Visual Studio 2008 is unable to differentiate between which project the file is being edited on behalf of.

This is illustrated by the following screenshot. Visual Studio assumes that _SOULFU_LIB is defined and therefore the large section of code that is covered can only be edited without the benefits of Intellisense.


Despite a decent amount of web searching I am unable to find any reference to a solution for this problem. I did encounter one other person having this problem, but the only helpful solution they were given was to wait for Visual Studio 2010.