Any svn gurus out here?

I've branch off from the trunk to do some work on a c# program.

Now it's ready to be implemented I've merged it back into the trunk.  But after doing this, the trunk wants a check in.  But how do i capture all of the log messages (check in messages) that I wrote in the branch.  They do not seem to be transferred across into the trunk.

And then what am I supposed to do with the branch, I normally remove them.  But I wont if it will mean I loose all the check in comments.

I'm using tortoisesvn and visualsvnserver.