@Haydz,
just to add to my post, i did a bit of digging and i *think* it comes down to what word i use for challenge. none of the online dictionaries seem to have challenge listed, so i tried 'test' and 'trial'. which one of the following would be closer to 'challenge' ?
periclitor, experior, experiri, expertus
and then according to some of the translators, it says it should be
"is (one of the above words) mos nunquam effrego mihi"
is this correct, or is there a better way of saying it?