Activity: Custom Activity Categories

Hi,

Small question in regards to activity categories.

We have created 2 custom activity categories: 'Graphical Design' and 'Structural Design' and we would like to link it upto a custom Transaction Type (copy based on 0000 - SAP standard appointment). Now we have linked these 2 categories to our transaction type (Assign Categories to Transaction Types) but we are forced to use the standard 'MT - Meeting' and assign it as well.

"Assignment of transaction type ZDES to activity category MT is missing."

Is there any way that when we create an activity, only the 2 custom categories are displayed? (MT - Meeting should disappear from the list)

Thanks,

Sebastiaan.