You can be on a FIS from a FIS unit, (Scottish Information for example) and in that case they'll have no radar picture of where you are.
You can also be on a FIS from a radar unit, and even be radar identified. being identified does not imply receiving a radar service (you could be outside the area of responsibility, or below terrain safe altitude)
If you're talking to a radar ATC unit, there's no need to squawk 7700. Just tell them you are lost, you can be easily identified (especially if transponder equipped) and provided with the most accurate fix.
Failing that, you can get a VDF fix.
Being lost per se is not gonna kill anybody. Entering IMC when not qualified, will.
I'd rather a VFR only pilot entered CAS without clearance, rather than enter IMC. It's easier to deal with an infringement than a CFIT.