Which IDE and version of VA are you using?
Using the very simple test code:
	int nLocalOne;
	int32_t nLocalTwo;
	
	nLocalTwo = 4;
	nLocalTwo = nLocalOne + 2;
both variables are being shown in bold by VA, they have the same colour, and all references to both are correctly highlighted when placing the caret into the variable name.
I am testing VS2010 with VA 1936