OK, removed the trim. This is easy. All your need is your bare hands, as I think if you use any instrument to pry off the trim you you risk to damage the glass. If you just hold the trim firmly with fingers and pull it hard enough it will come off.
Start from lower edge of the trim. Hold it with your fingders and lift it to the direction perpendicular to winscreen. When it came off the first retainer go to the next one. There are 10 retainers riveted to casis of the car. 3 on each A-pillar, plus 4 on the roof.
Below are 3 pictures of retainers after old trim had been removed and area below the trim had been washed. Fortunately for me, there was no rust there. On the first picture you can see first retainer, which is about 10 centimiters from egde of the trim. All in all, removing this trim is not very difficult.
