The Freeview DVB-S EPG is transmitted using the standard EIT table in the signal. This is the standard for EPG's and and virtually all boxes on the market support it, even unapproved ones. This is unlike the Freeview|HD EPG which requires MHEG5 support.
Maybe somebody else on here has played with one of those boxes, I personally haven't.
*Need help configuring your Linksys ATA or IP Phones for New Zealand? Check my blog post