Cutting the Lid on a MegaPot

I have been using a 15 gallon MegaPot from Northern Brewer as my brew
kettle. I love it. The only issue I have is when I use my Immersion
Chiller, I can't put the lid on all the way. I am sure many of you
that use a brew pot may have the same issue. I hear Stainless Steel is
tough to cut or needs a special saw. I guess my question is... What
does it take to cut a notch out of the lid of a stainless steel brew
pot? Am I better getting it done by a professional or can I use my
RotoZip or Dremel to do it?

Thanks,
Jeff