source above 0x8000 not mapped for debugging

I am using a Cygnal processor with 128KB Flash. For functions located above 32K (>0x8000) the debugger stops and gives me only the disassembly view. It does not offer the source at all.

FYI:
C51 v7.03
A51 v7.03
BL51 v5.02

Thanks for any ideas!