Hi Sami:
I had serious Cathe withdrawals too while doing P90x. What I did to "get my fix" was more Cathe cardio and I blew off most of the P90X cardio. Also, I tried to incorporate some Cathe leg workouts, since I wasn't feeling I got enough w/ P90X. Also, I did the Doubles rotation and did my cardio first in the morning (when I could) then my P90X strength training later in the day).. It was tough and I think I pushed myself a bit too hard into the overtraining zone.
Monday: CTX Kickboxing(or moderate 30 minute Walk) AM
P90X Upper Body (whatever one is in the week you are in PM
Tues: Circuit Max (used very heavy weight and did none of the upper body movements in this workout, making it a total lower body circuit workout)
Wed: CTX 10/10/10, or run for 30 minutes, or first half of MIC AM
P90X Upper body workout (whichever one for the rotation
Thurs: REST
Friday: first half of KPC, or Cardio Kicks AM
P90x leg and back tape
Saturday/Sunday: I blew off the Yoga and stretch tapes, because I just didn't like the P90x ones and did a long run on one of these days and a moderate Cathe Step tape on the other.
Looking back on what I did, if you feel you need more leg strength training you could do it on Sunday.. Legs and glutes would work nicely instead of doing a step tape like I did.
Hope that helps.. Keep us posted on how your progress goes.
Lynn M.