Erik,
currently no specific in circuit emulator is supported, uC/51 comes with its own Source Level Debugger (needs download to XRAM). A future Version will support Flash debugging (already prepared). Other output formats are BIN and HEX...

I'm thinking of adding OMF51 as output format, but before that I'll finish the www.Flexgate.com project and add the last stage to the optimizer.

Jürgen