VFR RV-6 with M98 TRACON for traffic advisories; maintaining clearance from Class B; assumed ATC coordinated transition of STP Class B when in fact ATC expected the reporter to obtain the subject clearance.

Narrative

I was returning to ANE Airport from CPS Airport and was receiving radar advisories from Minneapolis Approach. I was told to proceed to ANE Airport but to remain clear of the MSP Class B airspace. I descended and took the most direct route from my current position; taking me directly over STP and through the Class D airspace. The floor of the Class B airspace is 2300 FT; so I was at 2200 FT. I use radar advisories frequently on cross country flights and when on a squawk code with Approach; Class D transitions have always been coordinated with the Tower; or I have been specifically told to contact the Tower by Approach before I enter the Class D airspace. In this instance I was not told to contact the Tower; but was asked by Approach when directly over the airport if I had called the Tower. I responded 'Negative.' At that point; Approach told me to contact the Tower at Anoka; my final destination. I am not sure if I did anything wrong; but I sensed the Approach Controller was not happy. I spoke with the other local pilots about the situation; and several of them had similar frustrations with not knowing if Approach would coordinate Class D transitions. It seems to be controller specific. I have decided from now on; I will ask if I need to coordinate the Class D transition; or if they will do it for me so there will be no ambiguity.