Can't debug Excel 2003 Addin (XLL)

My problem:

I'm currently working on both an XLL (written in C++) and VSTO developm开发者_高级运维ent. I'm using Visual Studio 2008 and Excel 2003.

My VSTO addin doesn't do anything exciting. My XLL provides UDFs to the end-user (mostly calculations)

I've only recently started on the VSTO addin, and noticed that now when I attempt to debug my XLL I can't attach to an existing Excel process. If I disable the VSTO addin then this problem goes away and I can debug the XLL by attaching to the process.

When I launch "debug" from my XLL project and have VS launch Excel and it loads both my XLL and VSTO I can debug the XLL. This isn't exactly ideal as it would be nice to be able to attach to an existing session.

This problem appears to be envirnomental, does anyone know why this is happening?

When you attach, there's an option in the dialog that lets you choose the kind of debugger you want. Click the Select button, ensure you have "Native" ticked.