Adaptec DirectCD is now ROXIO DirectCD
VOB Instant CD/DVD - is now Pinnacle http://www.pinnaclesys.com/ProductPage.asp?Product_ID=1152&Langue_ID=7
- which so far, is the only other one I've seen which seems to support Packet format on CD-R media
DirectCD is supplied with Roxio Easy CD Creator, and with Cequadrat/Roxio WinOnCD
The best you can do with the supplied software, is to write multisession from Nero - though you would need to batch-up your writes, as you take a considerable overhead for each session.
Packet on CD-R can be rather tedious anyway - while the session is open for packet writing, it can only be read in a writer with compatible Packet software - in contrast to CD-RW packet, which can be read using a free UDF reader in any drive that supports CD-RW media.