Set Invoice number using code when running FUNAUTINVD

SOLVED

I am trying to set the invoice number manually using code, because of the clients requirements I cannot use sequence numbers. 

I have successfully accomplished this within SPESIH $VERIF_CRE.  However, when running FUNAUTINVD, this is ignored.  I have tried using the entry point but this will not retain the assigned invoice number.  Is there another entry point that needs to be used in order to manually assign SIH.NUM when running FUNAUTINVD?

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$VERIF_CRE
Local Char YINVNUM(30)
If [M:SIH0]SIVTYP = "INV"
  YINVNUM = "some invoice number"
  [M:SIH0]NUM=YINVNUM : Affzo [M:SIH0]NUM
Endif
Return

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$ALISIH
Local Char YINVNUM(30)
If [M:SIH0]SIVTYP = "INV"
  YINVNUM = "Some invoice number"
  [M:SIH0]NUM=YINVNUM
  [F:SIH]NUM=YINVNUM
Endif
Return

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