I don't know what characters 00-09 are and I don't think you can send the backspace key.
But you can emulate a delete using the the Set Selection and Cut script steps and the Get ( ActiveSelectionStart ) function.
By using set field or insert calculated result, you can use the Char function and specify the codes for the characters you want to put in the field.
David, char 08 is the backspace key. I am already using the set selection  and cut  functions for that purpose. I was looking for a single function result rather than having multiple functions to delete a single character (or selection) in a parser script.
PhilModJunk, there is no Char function in FMP7, or FMDev7. That function originated in FMP10. I cannot afford to spend any more money on another version of FMP or FMDev other than what I already have.