Force a higher refresh rate?

I'm using latest Knoppix version with kernel 2.6, running it in a 30gb hdd with a:
Samsung Syncmaster 550v 15 inches monitor
Nvidia GEforceII TI 64mb

Everything works fine except that the current (and only) resolution and refresh rate I can get is 1024x768x60hz. Higher refresh rate mode are no present.
My current Windows XP resolution is 1024x768x75hz and it looks great.
Is there any way I could force a 1024x768x75hz into knoppix and "save" this configuration so I don't have to change it over and over again?
Yoo know, the 60hz RR it's burning my eyes! :(

please help! :(

Type as root in a shell: "/usr/bin/kxconfig". Here you wil be able to set your display settings.

It worked great!
thanks for your help