I do not have a UCM 4.3 system installed any longer to see if this service parameter exists in that version; however, current versions have a Insert Hyphens in 12-Digit Numbers. This only works if you're setting the Caller ID to include OffNet access digit.
This parameter determines whether Cisco CallManager formats an incoming,
12-digit phone number with hyphens to enhance readability. This parameter
applies to phones that are using the Skinny Client Control Protocol (SCCP). For
example, instead of 911235554567, Cisco CallManager inserts hyphens, so that the
phone displays 91-123-555-4567. Valid values specify True (insert hyphens) or
False (do not insert hyphens).