Ok, so I have made my pumpkin breads again, but this time it didn't work... therefore I got to one big conclusion: don't use soya flour that doesn't look like flour!!!!!!!
The first times I made the recipe I've used soya flour bought in Portugal, and it did look like "normal" flour. This time I bought it at Holand&Barrets in London and it did look a bit weird, not "fluffy" as flour is supposed to be, and NO, it didn't work at all!!! So be careful with the flour you buy, maybe just use rye flour or a whole wheat flour if you wanna be healthier!