I understand your dilemma. I also import from a version 9 database nightly into SQL. 10 is supposed to be coming soon here...
I'm afraid I can't offer much in the way of a workaround. This is always an issue when we do a dump/load of Progress. Rather than make Progress db changes, we trim the fields that cause the issue. In our case, there are just a couple of tables with some older data. Seems the manufacturing package does a better job of limiting that now.
When we first began the import process some years ago, we used txt files from Progress rather than direct query to the db. Adds a step, but possibly would allow you to better control what you input to SQL.