They made a sample of the profile but it was slightly different regarding shape and thickness, so I thought it would be pointless to make more of this and insructed them where and how should it be corrected. They told me they had to work with another type of rubber that they didn't have in stock, and would arrive by the end of December. So as soon as the holidays are over, I'm gonig to visit the company again to check if they made some progress.
The answer from the rubber company is "we are still trying to produce the correct profile shape". I think they simply can't come to an acceptable result, so I 'm searching for another company at the time. It's not easy - there are very few of them here.