Stored Procedure with Firebird

I am using DF with a Firebird 3.0 DB. When I try to call a _proc it will not be found. When I try to show all _proc or _func procedures/ functions, the resource is always empty.
I rebooted the server, restarted Apache, but DF doesn’t show the procedures and cannot call them. How can I fix it? I need the SP.

This is a dumb question, but did you flush the cache? I’ve forgotten this step more times than I care to admit…

Yes, I selected “Flush System Wide Cache” and hit the flush of “firebird database”. Both several times.

It would be interesting whether anybody can successfully access STORED PROCEDURES in a firebird database via DreamFactory. If yes, what version of firebird and DF are you using. That might give me a hint whether it is “just” a version issue.
Or does anybody have enough inside to the source code of DF to give me a hint, where I could look for an error in the firebird or other modules that might be the problem that SPs are not shown for firebird 3.0 databases?