How to assign Program Change (PC) in an Instrument DEF?

Hi, can easily assign Program Change to a Pot on the Hapax, but I would like to put it also in the Assign Section of an Instrument Definition Text-File. Here is the the Assign-Section of my Instrument-Def for the REV2. I would like to assign PC to Pot number 5. Is this not possible?

1 CC:32 # Bank Change
2 CC:102 # Cutoff
3 CC:17 # FX Mix
4 CC:7 # Master Volume
5 NULL # PC - HOW ???
6 CC:103 # Res
7 CC:16 # FX On/Off
8 CC:33 # Arp On/Off

In theory it should be supported, but in practice I can confirm it does not work. I’ll file a bug report.