It is possible to define in Sharepoint Workflow, in Update List Item function, which column in specified list have to be updated by variable?
You could use a series of IF statements within the workflow to compare the variable to a known value.
IF variable isequal value1 set field X in list y
In this case you would need to list all 48 potential values in separate IF statement blocks. It's cumbersome, but in the absence of loops (which aren't available in workflows) it works :)