You are right about releasing the rear brake, in my case 2 things happened, the rear had only been locked for a couple of feet and the bike was still straight, it had not started to come around, or a high-side would have been likely. I fully released both brakes before the swerve, so was able to maintain traction even on the wet pavement.
The other thing I did right or got lucky with was that I avoided target fixation, I was looking at the clear path beside the van instead of at the van. Only looked at the drivers wide eyes when I was far enough to the left.
Luckily, no traffic behind the van, as to the left was my only option as she had the driver's front tire to the curb on the right at about a 30 degree angle to the road.
I agree that I was lucky, probably more lucky than good, but the point was that the MSF training (I've had both beginner and experienced) was probably what saved my rear.
It's not paranoia if the ARE out to get you.
2003 VN 750 "T'Pol"
Memphis Shades windshield
VN750.com radiator cover
Jardine slash-cut exhaust
Turn signals relocated
Ram GPS mount
12 volt power outlet
Airhawk II seat cushion