Just learn them, unfortunately. The time period between learning all 21 and only knowing a few will be unpleasant, but it's doable. Also, some of them are very similar to one another, Badmephisto's site groups them well (although his F perm is nasty).
For example, T perm is this: R U R' U' R' F R2 U' R' U' R U R' F'
J(b) is the same, but with the R U R' F' at the end moved to the start: R U R' F' R U R' U' R' F R2 U' R' U'
And the F perm I use is R' U' F' [T-perm] F U R