Field Data (^FD) and Field Numbers (^FN)

Hello,

How do I embed a field number into a field definition?  

Consider the following ZPL:

^FD51,0,6,111111,2,33,^FN11"Enter Barcode"^FS

The full ZPL is supposed to scan a barcode and use its value in the last parameter to fill out the EPC data structure:

^XA
^DFE:RFID^FS
^RB96,8,3,3,20,24,10,28
^RFW,E
^FD51,0,6,111111,2,33,^FN11"Enter Barcode"^FS
^XZ

How do I embed a field number into a field definition?  

Thank you,

Paul.