perl Tk button autorepeat

I am not able to get a Tk button to auto-repeat on hold-down.
Using activestate 5.8.4

These are the bare-bones of my latest of many different attempts :

$myBut=$dateFrameA->Button(-text=>"- -",
-width=>2, -height=>1)
->pack();

$myBut->bind('<ButtonPress-1>'=>sub
{
# button callback
});

$myBut->configure( -repeatinterval=>'100',
-repeatdelay=>'100');

Any thoughts would be appreciated