"Instead of trying to debug from vs.net, we tried to debug the dll source from vb 6, by starting the dll with run, in debug mode. After this, i've removed the original reference to vb dll, and added the reference to .vbp in vs.net. while vb is in debug mode."
Just to clarify, did you try to debug first while the vs.net project was still pointing to the dll? If not and you switched the reference from the dll to the vb 6 project first, then I'd retry this with the vs.net project pointing to the vb6 dll, keeping the vb6 project running in the VB6 IDE, and making sure the VB6 project properties have binary compatibility set to the correct version of the dll.
