well, you don't mention what version of Access you're using. the following
code runs on an A2000 database, running in Access 2003. i'm not sure if it
will run in Access 2000 or not. you can paste the code into a public module,
as

Public Function isBackup()

   Dim str As String
   str = "Back Up Database..."

   CommandBars("Menu Bar").Controls("Tools").Controls("Database
Utilities").Controls(str).accDoDefaultAction

End Function

note the entire command, which begins with "CommandBars(..." must be on one
line in the database, not line-wrapped as it is here in the newsreader. you
can call the function directly from the button's OnClick event property line
in the Properties box in form Design view, as

=isBackup()

hth

Roger's Access Library also has a sample database to show how to do this.

http://www.rogersaccesslibrary.com/download3.asp?SampleName=CompactBackEndDB.mdb