creator MSVC debugger problem

Hi,

I'm using creator 1.2.1 to debug a project build with Qt 4.5.0 with MSVC.
I am able to set breakpoints and start debugging.
The problem occurs on trying to step into a constructor (F11 on a line where i execute new MyObject();).
The debugger does not jump to the ctor as expected but instead jumps inside of some functions of MSVCR90D. I can't see anything happening in the code window (since the code is unavailable) but the stack trace gives me this after pressing F11 a few times:

Code:

---

0	ntdll!RtlEnterCriticalSection		0	
1	MSVCR90D!lock		0	
2	MSVCR90D!malloc_dbg		0	
3	MSVCR90D!malloc_dbg		0	
4	MSVCR90D!malloc_dbg		0	
5	MSVCR90D!malloc		0	
6	MSVCR90D!operator new		0	
7	syncpoint!MainWindow::init	mainwindow.cpp	68	
8	syncpoint!MainWindow::MainWindow	mainwindow.cpp	17	
9	syncpoint!main	main.cpp	38	
10	syncpoint!WinMain	qtmain_win.cpp	136	
11	syncpoint!__tmainCRTStartup	crtexe.c	578	
12	syncpoint!WinMainCRTStartup	crtexe.c	403	
13	kernel32!BaseThreadInitThunk		0	
14	ntdll!RtlInitializeExceptionChain		0	
15	ntdll!RtlInitializeExceptionChain		0

---

The problem is frame 6 and lower. When i keep pressing F11 it keeps on executing different functions inside MSVCR90D. Also manually setting a breakpoint inside the constructor and hitting F5 does not help, the debugger does not stop inside the constructor.
Does someone know how get the debugger to jump to ctor of my class instead of doing this? I installed the debug helper for the qt version i'm using so this should be fine i think.