Cannot debug RTD Excel
 

I've created C# (or VB) RTD Server that works OK. However I cannot
debug it. The server is created as .Net class library with "Register
for COM Interop" checked. Project properties: In Debugging, I set
debug mode to Program, and Start Application to Excel.exe. When I
start MyRtdServer in debug mode it calls Excel, and Excel starts. In
Excel, I open my test .xls file (frankly, very simple, with just one
cell with RTD formula) and it immediately closes the Excel window
without stopping on my break point, which is set in the very first
line of the RTD object constructor.
If I start Excel and open the same .xls file in release mode all the
stuff works.
What should I do in addition to allow debugging?
I use WinXp, VS2003 and Excel11.
Thank you,
Alex Zhitlenok