Vanessa,
I suggest you read this:
http://www.deanwesleysmith.com/?p=4096
Worth reading all Dean's posts on the subject actually, and his posts about agents. Here, he's talking mostly about agents offering to publish their existing clients' backlists. But the principles apply to new authors, too. Publishing is going through huge changes at the moment, brought about by the rapid increase in e-book sales. This has publishers very worried but has agents terrified. Hence, they are trying to get in on the act before writers realise they don't actually need agents (or even publishers), but can do it themselves.
Very nice of Create to let you keep the copyright! But 50% of the profits? For doing what exactly? Anything they do, you can do yourself. Yes, you may need to pay an artist if you want a decent cover, and an editor if you want the book to be well put together. But after those costs, you'll make a lot more than 50%.
There are some new e-publishers working much more as collectives, i.e. you keep all the rights to your books, and most of the profits, just using the publisher if and where needed for services you can't do yourself. Better to check out these, I'd say.
Terry
<Added>Just to emphasise, Dean's series on Think Like a Publisher will tell you a lot about self-publishing.
I think what's rather smelly here is that this publisher clearly got your details from an agent. Which suggests have some kind of stake in the company, which I'd say is bordering on a conflict of interest.