Wood windows and doors with Vinyl siding?

Is anyone else having problems keeping paint on wood windows and doors when the house is wrapped in vinyl siding.
On the new construction houses Ive been doing for the past 12 years, Ive been seeing it happen with in about two years. But Ive seen others fail a little sooner, id assume do to the quality or lack of a second coat. The ones done in oil really go fast.
I also had it happen to wood windows in a house i bought about 6 years ago. When i bought it most of the windows where in good shape (10 years old original paint) but the ones in the back that where facing the weather where starting to peel.
Well i scraped/sanded/caulked/glazed/.Every thing you'd expect a good painter to do, especially to his own house. Primmed and painted with quality paints from Farrell Calhoun's. Still my preferred out side paint.
Well I'm not to sure on the exact time frame now but id say with in 8 months they where peeling again. As far as i no the sills are bare rotten wood now, unless the new owner likes painting real often.

Id assume this problem has to be a moisture problem. Where the rain is getting between the siding and wood. Since it even takes off the factory primmer on new door casings. And it starts lifting on the outer corners first.
How is every one dealing with this problem? Warranting would be my major concern. Which is why I'm asking. Since new construction is down I'm looking for repaint work. But i shiver over the thought of any peeling paint after seeing my own windows fail over and over.
Does any one clear caulk the J channel to the wood. Thinking it would help some but clear caulk becomes dirt covered in short time. At least in new construction where red clay dust get stirred up all the time. Is there a brand that doesn't?
Any ideas, comments, or peeling experiences?