First, you need to add the commands to register and unregister at install and uninstall respectively in the CustomAction table (| denotes a column change):
UnregisterProdesktop | 18 | F59122_ProD.exe | /unregserver
RegisterProdesktop | 18 | F59122_ProD.exe | /regserver
Then you call the aforementioned actions from the InstallExecuteSequence table:
UnregisterProdesktop | REMOVED="ALL" | 1450
RegisterProdesktop | REMOVED<>"ALL" | 6650

