You could try this behind a button:
Dim strOle As String
strOle = "c:\my documents\Test.doc" 'this can ref a control
Me!YourBoundOLEControlName.SetFocus
SendKeys "%f,%e" & strOle & "{ENTER}"
RunCommand acCmdInsertObject
There probably is a cleaner way to do this, but for the life of me, I can't find it.