Support for BT Vision was made available for PUC's which means flash updateable from a PC in September 2008
However, BT Vision is NOT available in any of the STB chips.
Last year B&O decided to group STB IC's by region due to the limited space in the software IC, the set-top boxes have been split into 5 ICs as below:-
North Europe, version 4.00 (part number 8344784)
West Europe, version 4.01 (part number 8344785)
Central Europe, version 4.06 (part number 8344786)
South Europe, version 4.03 (part number 8344787)
Asia, version 4.04 (part number 8344788)
This was also seen as the final chip update, in other words they were not expecting to update them again because BeoVisions which have shipped for some years now have PUC's which are soft updateable.
So, to be clear a STB (Set Top Box) Controller and a PUC (Peripheral Unit Controller) do exactly the same function for the user, however the STB controller can only be updated by chnaging a chip, but the PUC can be updated using a PC.
Unfortunately your Beovision 5 has a STB controller, so you do not have support for BT Vision and I would be surprised if the chipset is updated again.