Problem enabling JIT debugging

[Mombiatch]

I've embedded a .NET User Control in my asp.net webpage using the

<object clsid="whatever.dll#namespace.calss"

tag. I'm now trying to enable JIT debugging so I can see where the
SecurityExceptions are being thrown. I followed the instructions to add

<system.windows.forms jitDebugging="true" />

to my web.config file for my app, this diddn't work despite doing an
iisreset and even a reboot. I also tried setting it in machine.config, to no
avail. Anyone know of any other settings I need for this to be enabled?

Thanks
Joe