Finally solved the problem....
Being só sick of all this at trying to adjust the shoes with no result I ordered a new pair of shoes. This time I ordered Wagner brakeshoes. The first ones were from Raybestos.
When they came in, I compared them with the Raybestos shoes. At first sight the were exactly the same but.....when I measured them it seems that the Raybestos were 0.5 MM !! wider than the Wagner.
Anyway, put the shoes on, adjusted them, took a test drive and...No heating up at al. Brakes work perfect now.

As some members here suggested already: shoes were not good altough they lóóked OK

Thank you all for your input in this..