You make either the value the same as the item text in Designer. You can unclick the box "Specify Item Values".
Or, if that is not possible for some reason, I would put a hidden text field that gets the item text of the radiobutton selected and do the binding on that field instead of the radiobutton. Workaround ...
I would love to do the first option, but the forms are already completely filled out. When I've experimented with changing completed forms, the values get erased. Is there a way of altering the radial button options without erasing data from the forms?
The second option also looks to involve altering the original forms and thus erasing the data stored in them.
Therefore, I'm not sure it will work
So, you are telling me that you have received numerous forms containing this issue and now you want to have the "corresponding" value in your data ? Why don't you run the extracted data through an XSLT that does what you want ? If you are running this in a server process, the only thing you need is a simple XSLT and one extra step in a process.
That is what I am telling you. I'll look into XSLT!