Logic pro does not "see" certain pads on my v-drum kit

Hi everyone,

I have a Roland td-11k drum set and a Roland UM-one midi interface. When I open Logic Pro with V-drums hooked up to my Mac, every pad triggers perfectly except the edge of my hi-hat (it's a two-zone hi-hat, and the top zone triggers just fine) - Logic Pro just does not seem to detect it.

The same situation is seen in Garage Band, but with a different pad - the edge of my crash cymbal (hi-hat works in GB).

Any help on this will be greatly appreciated - I am an absolute newbie in Logic Pro.