OK, let me take this one step at a time.
A pilot qualified to fly in IMC (which is the IMCR or the IR; the difference between the two is less than perfectly plausible differences in pilot currency) enters IMC accidentally, and knows that he is below the MSA.
He should know enough about where he is to know which way to turn and climb, perhaps? In which case a PAN would be right if he's going to bust some airspace, or the field has an IAP and there might be instrument training going on.
How can anyone on the ground help him, if he's close enough to the terrain to think a straight ahead climb is not safe? Only an existing radar service would be of help in the available time. And if he is far enough away from hills etc he can just climb up, surely?
I am trying to get away from knocking the IMC Rating. It's nothing to do with it. A 25,000 hour ATPL, finding himself in IMC below the MSA and unsure of which way to go, will be in the same position.
One should NEVER fly below the MSA, VMC or IMC, unless taking off or landing. I suppose one could "discover" a cloud on a long final in a "few at 600ft" scenario .. but then climbing straight ahead should be OK; how many airfields around the UK have a 600ft hill at the far end of the runway, on the runway heading?
If I was totally lost after some prank like that, I would spend my brain capacity in such a dire emergency on getting out of it, getting some orientation sorted out, not making radio calls. Autopilot (if you have one) on immediately, a rapid climb, GPS and the chart.
Sorry if I am missing something here...