Amazon Echo Control: Problem with TuneIn station with six digits

Hello, I have finally installed my Echo Binding in the last few days, but unfortunately, I have no way to activate the radio station I prefer via TuneIN (NDR2: station ID: s228737). As far as I can see, the problem is in the length of the station ID of the transmitter. Four or five-digit sender IDs are accepted; the six-digit sitemap does not build up at all.
Who knows this problem and is there a solution?