Hi Emmanuel,
the easiest thing would be to split up your ROM part in the .prm, something like this:
ROM1 = READ_ONLY 0x1900 TO 0xBDFF FILL 0x8D; /* fill with an ILOP */
/* Gap for 0xBE00..0xBE02 where we writhe SoftWareVer[3] */
ROM2 = READ_ONLY 0xBE03 TO 0xFFAD FILL 0x8D; /* fill with an ILOP */
You will need to update the PLACEMENT as well to reflect ROM1 and ROM2.
Erich