Annie, I found a fairly simple solution. Under Survey Settings\General Format\Navigation Buttons\Settings\Submit Button, write some Perl code that references the page number.
If you are on the first page, show the button label "Begin Survey". If you are on the next-to-last page (the one before your Term/Link question) show "Submit". All others show "Next."
This code by itself does not remove the "back" button. But I suppose some fancy CSS work may be able to accommodate.
[%Begin Unverified Perl
if(PAGENUMBER() == 1)
return "Begin Survey";
elsif(PAGENUMBER() == TOTALPAGES() - 1)
return "Submit Survey";
return "Next >>";