Conversion of Netware 5.0 Arcserve DAT t

I have about 70 DAT and DLT tapes that were written to using Arcserve for Netware with compression enabled. I have changed over all servers to NT and now I can not restore any data on the tapes into Arcseve for NT. Does anyone know how I can convert the tapes to be usable in NT. I heard rumors that there are places to get this done. My company would pay $100 per tape if necessary. Thanks for any help