Cast to typedef in Visual Studio debugger

Hi, when I'm debugging my application and add a variable to my "Watch" window. I can cast it to qreal there and get the correct value as a double (qreal is a typedef for double in qglobal.h).
But when I try to cast to my own typedef I get a "bad type cast" error message.
The "Type" column is also empty for my type, but for the qreal cast it says "double".

What can I do to be able to use my typedefs in the Watch window?
I crawled through my Visual Studio installation directory searching for qreal, but it did not find anything.

Ginsengelf

PS: Visual Studio 2005, with Qt Add-in 1.1.9, but I'd appreciate any ideas.
PPS: added image. lWidth is an integer, int32 is my typedef for integer