Does anybody know if any cd burning programs support multisession writing?
Brasero supports multisession burning. Also, if you are comfortable using the command-line, wodim supports multisession burning, and you should already have it installed. From the wodim man page (the -multi option):
Allow multi session CDs to be made. This flag needs to be present on all sessions of a multi session disk, except you want to create a session that will be the last session on the media. The fixation will be done in a way that allows the CD/DVD-Recorder to append additional sessions later. This is done by generation a TOC with a link to the next program area. The so generated media is not 100% compatible to manufactured CDs (except for CDplus). Use only for recording of multi session CDs. If this option is present, the default track type is CD-ROM XA mode 2 form 1 and the sector size is 2048 bytes. The XA sector subheaders will be created by the drive. The Sony drives have no hardware support for CD-ROM XA mode 2 form 1. You have to specify the -data option in order to create multi session disks on these drives. As long as wodim does not have a coder for converting data sectors to audio sectors, you need to force CD-ROM sectors by including the -data option if you like to record a multisession disk in SAO mode. Not all drives allow multisession CDs in SAO mode.