SR22 pilot requested an IFR clearance from ATC to descend through a cloud layer; thinking ATC had issued an IFR clearance the pilot descended only to later realize he was still under VFR.

Narrative

Eastbound VFR at 9;500 receiving advisories from Cherry Point Approach; inside restricted area R5306A (approved by Cherry Point); enroute to W95; Ocracoke Island airport. No ATC issued restrictions to altitude or course (VFR in Class E). Weather was forecast to be few-scattered at 3;000; but ended up being broken with bases 3;000 - 5;000; tops 9;000. I had heard a couple 'stumbles' from Cherry Point ATC to other aircraft and what sounded like a Supervisor's voice coaching the ATC personnel (Trainee?). Then the following conversation occurred between myself and ATC: Me: 'Cherry Point; Aircraft X; request 'ATC: 'Aircraft X; go ahead 'Me: 'Aircraft X; the clouds are thicker than forecast; would it be possible to get an IFR clearance present heading with a descent to 2;000; and I will cancel once I break out and continue VFR? 'ATC: 'Negative; stand by 'Me: 'Aircraft X; roger; if that's too much work; I can maintain VFR and spiral down through a hole; but the IFR clearance would make it easier for me.' (About 30 seconds) ATC: 'Aircraft X; turn right heading 170; descend and maintain 7;000.' Note the use of an IFR altitude; a descent after I had requested an IFR clearance to descend; and the specific heading instruction (not typical for a VFR flight in Class E with no other traffic). So I assumed I had been issued an IFR clearance even though it did not follow the 'CRAFT' clearance format. I almost queried ATC to verify I was IFR; but I felt a little bad that the Controller/Trainee kept having his Supervisor correct him; and I also felt that I had already made life difficult for ATC; so I acknowledged the clearance; flew as instructed; and kept my mouth shut. Clearly; this took me into the clouds. Later I was stepped down to 5;000 FT (another IFR altitude) and broke out at that point. I was switched to the next controller; who asked if I wanted to start my descent to W95. I replied 'affirmative;' and the Controller just said 'descent your discretion.' Note no altitude restriction. Clearly he thought I was still VFR. Which means I may have gone through clouds while not on an IFR clearance! I was in VMC by the time the descent instruction made me realize that I may not be IFR; so by this point there wasn't much I could really do. A few suggestions for both myself and ATC; and possibly FAA. For Me: Make sure I always clarify whether I am now IFR in a similar situation when a full 'CRAFT' style clearance is not issued. For ATC: In the situation above; if I was supposed to have been VFR; they shouldn't have descended me after I said I'd need an IFR clearance to descend - or at the very least they should have said; 'maintain VFR.' If I was supposed to have been IFR; clearly that information did not get handed off to the next Controller. For FAA: If this happens frequently; perhaps when picking up an IFR clearance when airborne; some new phraseology is in order to explicitly signify when the flight has switched to IFR and receiving IFR handling; rather than just the 'cleared to...' phrasing used today.