To be honest, I don't fully understand that sentence either. But I assume it means something along the lines of "I'll write some BL stuff under your editing", or simply put: "I'll write some BL stuff for you".
Ah, I think I got it! Google told me that Kawamoto has changed his post and apparently works in a BL-department now. So it means "I'll write some BL stuff for you at your new post if you wish".
Ah, and I have bad news for you. Eiji Mikage, the author of Utsuro no Hako to Zero no Maria, has started a new light novel that will be published in July. Its title and plot summary both sound pretty... well, read for yourself, and chances are that Hakomari has been discontinued, though nothing is set in stone yet. But at the least, it's safe to assume that his writing pace is going to drop even more.
I won't stop trampling on you until you cry!
Author: Eiji Mikage, Illustrator: nyanya
Let me report the situation. I got on all fours and was used as a seat by an elementary schoolgirl. I had my bottom slapped by her. What the hell is this? Why have I become the horse of a girl child? Yeah, wait for the follow-up report.
I'm probably going to read it anyway, but I have absolutely no expectations. Fortunately, there are still three older lns by him I haven't read...