I'm using FB 7490 behind the bbox3 because of Netflix. If you don't have/need Netflix, you can connect the FB directly to the proximus cable, thus without bbox3, and Proximus tv will be working.
Without the bbox3 the easiest way is by the wizzard. First check if you have the latest firmware 06.52, System => set the language, country and proximus as provider (better avoid proximus tv), just follow the wizzard, select Annex B (but it seems A is working too !?) or Internet => settings => internet access => select provider proximus.
Here are my settings (using bbox3): First check if you have the latest firmware 06.52, System => set language and country Belgium, Select Proximus instead of proximus tv, Internet => access select existing access via LAN, you may connect the decoder to LAN ftp://ftp.avm.de/fritz.box/fritzbox.749 ... e/english/
More details about FB 7490: viewtopic.php?f=24&t=88912&start=520
Voip: Fritz!Box 7490 Weepee + MegaVoip, postes dect + filaires. Proximus start + tv, Netflix, Spotify premium, mobile Dommel