new field in field catalog?

Hi

I have a requirement to create a new condition type that captures the value maintained in the material master tax price 1 (MBEW-BWPRS).

Will be enough to create a new routine to pick the value from MBEW-BWPRS or do I need to add this field to the field catalog in order to use it pricing?

Will be Thankful if someone can help me with the steps in achieving this.

Thanks

Satish