Hi ,
Normally we use VK11 to maintain tax condition records
. If you know the key combination, it would be good to use VK11 for any individual condition type
But VK31 is used for mass maintenance of Condition records for more than one condition type at a time ( for example MWST ,PR00, K004 K005)
MWST basically should contain Destination country and departure country as combination. Irrespective of Order type if above condition record is maintained, system will automatically determine the condition record for any order type
If you wish to have Sales order type as one of the key combination, then you can very well include in the access sequence as one of the field and maintain accordingly
hope this is clear
thanks
santosh