[rules-users] Drools decision tables — calling functions inside value cells

I am looking to use drools decision tables for a project. I want to add a condition where I verify that the value of a passed in object is less than a specified number. I want the decision table to look something like: http://imgur.com/gf1Twb4 If you look at the third condition where I am checking the max size of the loan, I am calling a function: $t.getStandardLimit($n). Unfortunately, I am unable to call the function inside the value cells with that syntax (drools reads it as a string and returns a syntax error). Is there a way to do this?