The text that the German poster received is above in post #10 and I have no doubt that this is genuine, but
Fl1ingfrog is correct in stating that you should not automatically assume that you'll receive the same response. Delving into this a bit further, it may be that the core of the issue is a bit further down the rabbit hole, as I don't think that ICAO ever catered for the situation of a SOLI.
FAR 61.75 is there to allow ICAO licences to be used as the basis for an FAA licence, but it clearly states that you can only use a single licence as the 'base' licence. As
fdl said, the SOLI situation is a different concept entirely whereby one state can issue a licence and another can take over the paperwork and issue a new licence to you. It is something that works in EASA-land but to a non-EASA state it may
look like a piggyback situation, especially with a different state listed as 'state of issue' on the paper certificate. Yes, they should recognise it as an ICAO licence and not worry about the history but I guess they're playing it safe in this respect. It wouldn't surprise me if ICAO has no guidelines on how to deal with this situation.