SyncBackPro V8 (or earlier) versions has built-in support for backup to CD or DVD (including Blu-Ray). It also supports automatic disk spanning. Note that CD/DVD burning is only supported on Windows 7 and older.
SyncBackFree and SyncBackSE (and SyncBackPro on Windows 8 and later) can only backup to a CD or DVD if it is pre-formatted in UDF format.
In SyncBackSE V4.1, to span multiple disks you must backup to a Zip file and enable disk spanning (Compression -> Advanced).