InputField (11,40) "Amount" (11,48) size=16 name="my_amount" Tab F[Reference] V[my_amount]
I also tried (equally unsuccessfully):
Tab F[Reference] F[my_amount]
For your own InputFields please use the field label:
Tab F[Reference] F[Amount]
You may also use the coordinates:
Tab F[Reference] #[11,48]