Equifax for CE 4 files

I have been looking to find the equifax certificate file to put into Aegis, but I can't seem to find on that is compatable.

Has anyone had luck finding on of these files?

Aegis seems to want a .cer , p7b , or pfx file format.

I have a .der that my school gave me, but it didnt like it when i changed the name of it.