Porting two WP 1.2 into one 1.5.2

Hi there, i have a personal website, with a few personal area’s of interest. I keep a list of book-reviews and, more blog-like, my personal ramblings. I chose, at the time, to use two different WordPress installations, both version 1.2

Now, the current version, with the templates, with the Pages, offers a lot more interesting things, and i am quite sure i can combine both blogs into one single blog. Using categories, using pages with their own loop (not quite sure how yet, but almost). The biggest problem i see, now, is how to import the data from both blogs into one single database.

I was thinking along the lines : start of with one blog, upgrade that one to 1.5.2. Add a new category for the other posts. Export the other posts, to an sql-file. And then i am thinking id’s, and how i could easily augment the id’s of the posts with the number of posts i am trying to import from the other blog. So they won’t collide.
So for so good, sounds reasonable, albeit somewhat tricky 😉

But will this work ?
Change the id’s ? what has to change as well ? For instance the post-id of the comments ?

So, is there anybody here who can give me afew pointers what i should bear in mind, to keep a working environment. Or is there an easy way to merge two blogs into one single ?

All hints will be greatly appreciated !! 😉