pa300 expression pedal can't be assigned to efx?

[musiccankill]

Hello!
I just came across the need to use the expression pedal as a trigger for the wah effect.I had done it on all other models with success and now i saw that it can't be done on it.
There is no option to assign the expression pedal to an empty midi CC# to use it at any place like all the other models.
Am i missing something obvious?
If not, i consider it a bug most probably.Can somebody confirm that this is the case?
Will there be a fix for it?
Thanks a lot