Using date entered by user - by: stuttgarter

I am trying to create question group as follows:

q1(dropdown): Class(C1,C2,C3)

q2(radio): Teacher(T1, T2, T3)

q3 (Date):

q4(textDisplay): UID is {q1}{q2}{q3} --> output is : C1T301.01.2013

I am trying to remove (.) from date and tried a couple of tricks (strReplace, and trim )but is not working.

Any suggestions would be appreciated.