I've come across a situation where I have to append a value from one text column to another text column. I would usually just do this via the front end of the application, but this is a data migration and has no such luxury. Ive experimented with text pointers and have only managed to add new data via the pointer, not append.
As was posted somewhere else - you can't really do this in SQL. Manipulating text columns has to be done in client apps, so if I were in your shoes I'd write a simple perl script to handle the migration for the tables that have TEXT columns.
A perl connection is the same as a C program connection (i.e. connecting with isql). It's not the connection that is the issue, it's what you do with it. (and yes, I'm sure you know this - but you might try to explain this to your management)