PlanningFunctions.getIdForString

I am trying to get the PlanningFunctions.getIdForString to work in a business rule using a substitution variable, can the function PlanningFunctions.getIdForString work that way?

I am using Oracle Planning in the cloud.

This compiles and works:

     ("RateTableNumber" = [[PlanningFunctions.getIdForString("MPO Burden FPR - 97")]];)

This will not compile:

     ("RateTableNumber" = [[PlanningFunctions.getIdForString({SubVar_NewRateTableName})]];)

I don't want a literal in a business rule that will need to be updated, compiled and deployed 3 - 4 times a year.

Thanks for any help,

Pearl Barr