Your best choice is likely going to be to apply a template to the phones you need changed. Hopefully, the button layout on all of them is the same.
Then you can do the find/replace, applying the template to the affected phones.
To create a button template, click System/Advanced/Create New Template... You then have several options for filling in the switch and button fields.
Hope this helps!
Dave Wolgast
HealthNow NY, Inc.