Is it OK to select an editor if I solved his conjecture? I am about to submit a paper to a respected math journal. In this paper I solved a conjecture that was raised by a member of the editorial board (and this is one of the main reasons I chose this journal).

When submitting, I need to choose a member of the editorial board to handle my submission. Given his relation to this paper, is it OK if I list this person as the requested handling editor? Or does this cause some problem?
In fact, I think that is the best choice!  That guy is likely to know more about the subject, and be aware of previous attempted solutions.