Printing czech character from SAP

Hey everybody,

I'm trying to print a ZPL coded label from SAP to our "new" Zebra ZT410.
We are using device type LB_ZEB and E:TT0003M_.FNT in the code.

I know .FNT is not supported anymore but Zebra says it switches to .ttf automatically.
Even changing to .ttf doesn't change anything.

Our old ZM400 is working with a E:ARIALBD.FNT in the code. But we don't know who installed this font in the past.
It's also printing with LB_ZEB device type and it looks good.

So this must have something to do with the installed Fonts.
Can you tell me which font I can install for ZT410 with TTF which should work then?

Our connection is via network where a printserver is between.

See attachments for visual details and ZPL Code