Thank you for your help, but its only half the truth (I've figured it out myself this morning).
You're right, its the F-Term, but its only a tricky way writing it. If you take the [tex]\Phi[/tex] you suggested, and construct a polynom out of different [tex]\Phi_i[/tex]'s and then only take terms of the Order [tex]\theta_L^2[/tex] you get my Term. To see this, take only the [tex]\phi[/tex]-Terms of the polynom but either two of the [tex]\psi[/tex]'s, or one [tex]F[/tex]. So all terms are of the order [tex]\theta_L^2[/tex]. If you now count the possibilities of replacing one of the possibilities [tex]\phi[/tex]'s with a [tex]\psi[/tex] (two times, so you get two [tex]\theta[/tex]), you get same factor as if you just take the whole polynom in [tex]\phi[/tex] and derive in respect to [tex]\phi[/tex]. Thats the whole trick in there.
You are right, I'm jsut learning SUSY, but Weinbergs is the best book I could find. In my opinion, all the other books are too brief or just incomplete, including Argyres or Wess and Bagger. And you're right, Weinberg is a hard text, but at least he gives enough motivation to the things he does. I'm only missing some comments here and there. So if you know a script (other than Argyres. I got this one.) somewhere, based on Weinbergs Book with some extra remarks and comments, that would be great.
And yeah, this is a students presentation. 5 weeks to go.
And again, thank you for your help.