When a client asks a vendor to do additional work that is outside the scope of normal custom and practice, the vendor is entitled to additional remuneration.  If I was in that situation, I would politely inform the company that yes, I will be more than happy to accommodate them; then I would send them a copy of my fee schedule for typing services.  You do raise a good point about the liability aspect, so you probably should run it by your E & O carrier first.

Hope this helps.

Regards, 
Scott Perry