Dell Battery not charging?

Anyone know how to get the battery to charge?
i've got a 2yr old Dell Vostro 1700 without a power adapter. i bought a Universal Adapter which powers the laptop, but wont charge the battery.
i have discovered that dell deliberatly wont charge batteries with nondell adapters (swines - i'm sure this is anti-competition!!)
Anyways, a bios upgrade didnt fix it
(just so you know, run the bios as
a:>A07 /forceit
otherwise it'll complain the battery is dead and wont upgrade)
So what do i adjust/break/solder to make my adapter charge the battery...
Thanks