Access 2000 equiv of InStrRev and Replace (1 Viewer)

[mik]

Hi, I have built a small application in Access 2002 saving in Access 2000 format. The application runs fine on Access 2000 except that the following SQL comnmands are unknown
Replace
InStrRev

Full syntax is;
DoCmd.RunSQL "UPDATE MSC_load SET MSC_load.FileName = Right([FileName],Len([FileName])-InStrRev([FileName],'\'))"

DoCmd.RunSQL "DELETE MSC_load.Internal_Key FROM MSC_load WHERE Left(Trim(Replace([Smmt_called_imsi],'F',' ')),3) = '505'"

What is the equivilant workaround in Access 2000 ?