Ok once again, the N900 will charge the scud 98% up, you will not really feel or get much more by the last %, the charger you link to will charge the N900, and then the N900 will still administer the charge, meaning if you charge from a computer, normal nokia charger or the charger you posted, it will still be 98%!!
The only way to get the last % is by making a system like mine, or getting a normal external charger (for battery only) and modifying it.