Unfortunately Speedtouch changed their firmware after the v6 (6.1.4.3) and removed some of the commands so that DMT tool wouldnt work with it.
Before you attempt to connect:-
From the toolbar "Special" > Misc Options try ticking the "Unlock experimental area" (modem options). Click Yes, Save, Close DMT and try connecting again.
Default login is Administrator with no password
I dont have a v7, so Im not 100% certain, but iirc you may be able to log in but cant do any of the tweaks... and the v7 is actually a different chipset more akin to those routers which use DMTtool v8