"Save and choose another" link

Look at the bottom of /pc/app-ViewPrdFuncs.asp for this code:

<div id="AddtoList" style="display:none"><%if popUpAPP<>"1" then%><a href="javascript:new_AddSPtoList(SelectedSP);"><%respo nse.write dictLanguage.Item(Session("language")&"_viewPrd_spmsg7") %></a><%end if%></div>

This code displays the text message, and that text is retrieved from the languages file:
<%response.write dictLanguage.Item(Session("language")&"_viewPrd_spmsg7") %>

Here is the languages file reference:
dictLanguage.Add "english_viewPrd_spmsg7", "Save and choose another"

You could replace the string Save and choose another (in the /includes/languages/asp file)with an image tag reflecting a reference to your button, or just replace the ASP code (in /pc/app-ViewPrdFuncs.asp) that calls the language reference. 

Either way, be sure to make a backup of whatever you change, and retain notes of what you change so it can be replicated after the next release upgrade.