Self-diagnosis is always difficult, even with the help of a book. Since you are reading the book in Dutch, may I assume that you live in The Netherlands? If so, there are two structural yoga therapist whom you might consult. See Mukunda Stiles’ site for address information. After a body reading, tests of ROM and strength tests a more accurate recommendation for your condition is possible.
Using the SYT book (Table 6) AND assuming your self-diagnosis is correct: hyperextended knees calls for strengthening the quads with warrior II, bridge, camel. Knock-knees calls for tree, warrior II and head-knee pose. Your feet out diagnosis is not clear to me. Knees forward with feet out could be tibial torsion - no recommended poses. On the other hand, if the feet-out rotation starts from the hips then the hip inner rotators need to be strengthened (and outer rotators stretched).
Again, correcting posture with yoga is best done together with a very experienced yoga teacher and most preferably with a yoga therapist. It also takes time and dedication. And finally - if your posture does not cause you any discomfort or pain - there is no need to change it at all. Best of luck. Namast?, Willem