how to put automatic count?

this is my code:

VB Code:
  1. calc_pm = "1e0010230014000d1004000100"

  2. last_pm = "000000000000000000560140"

  3.  
  4. xor_pm = XorHex(calc_pm & "00" & last_pm)

  5.  
  6. FT_RES = SendToDevA(calc_pm & "00" & last_pm & xor_pm, &H1)

  7.  
  8. cH = ""

  9.     For i = 34 To UBound(FT_In_Buffer)

  10.         cH = cH & Chr$(FT_In_Buffer(i))

  11.     Next i

  12.     ConvThisText = cH

  13.     ConvToHex ConvThisText

  14.     cH = ConvThisText

  15.     

  16. pm0 = cH

you will see the "00" after the string readed from pm0 = cH
need to change immedietely the "00" into "01" and save into new string perform again.. "01" change into "02" and save it in another string.. up to 10