ISAPI Filter Programming

When you set up an ISAPI filter using IIS you have to enter a Filter Name along with the DLL to be used. Does anyone know how to access the name that was entered.
We would like to make it so that the name you enter for the ISAPI filter is the name of the config file that the ISAPI filter will use.

Right now we have the name of the config file statically coded into the filter. SO that means we need to recompile the DLL with a hard-coded config file name for each site that needs different config options.

We would like to have the filter name - or some other method of specifying the config file - so that there is only one copy of the DLL on the computer, and multiple config files - rather than multiple DLLS and multiple config files.

Perhaps something here will be helpful. I've never embarked in isapi programming

http://www.iisfaq.com/default.aspx?View=P11&P=1