cracking thomson router modem access code algorithm

as there exist tools to calculate default wifi wep/wpa key for thomson routers some of them further require MODEM_ACCESS_CODE in order to be able to modify it's configuration.

so i ask here does anyone know how to calculate this code based on serial number or mac address?

the closest i came so far is reply from andygot in this site

Code:

http://forums.modem-help.co.uk/viewtopic.php?t=1340

but it's not working for this newer thomson models

the router in the pic is in question