can't debug System.Management objects

I wonder if this is a .NET bug or something I'm doing
wrong:
In my code I have a function using ManagementScope and
ConnectionOptions objects from the System.Management
namespace.
My problem is that when I use this function, from that
point on in the code, the debug breakpoints does not work.
If I put a breakpoint before calling this function - they
work, but afterwards - nothing! When I set a breakpoint
before calling this function and then try to "step into"
or "step over" it - a message box jumps from the Visual
Studio -
"There is no source code available for the current
location"
When I remark all lines in the function that involves
ManagementScope and ConnectionOptions the problem
disappears.

It would help me a lot to know if this is a known issue
and if there is some kind of a fix for that.

Thanks,

Haim.