Mercury Mountainner and rear facing convertibles...your suggestions needed!

[mtnbaby]

We live in the middle of nowhere so trying out rear facing convertible car seats is not an option nor do we have a certified CPS nearby to help us check our new seat so I am appealling to you all...
My 6 mo old is about to make the jump up to a convertible seat in a Mercury Mountaineer. We want her to be in the MIDDLE, REAR-FACING and there is NO LATCH.
We ordered Graco Comfort Sport which was recommended in the book as a good second carseat and travel carseat (she has a Britax Roundabout in our main car)--we want a small, easier to travel wtih carseat for the second seat.
Grace Comfort Sport could not be tightly fasten in any way, shape of form in the rear facing position!!! We took it to the state patrol, car dealership and car seat store.
I checked the carseatdata.org and nhtsa.gov sites but with no specific help as to REAR-FACING suggestions for this car...

1. What is the deal with convertible car seat recommendations that seem to only apply for the forward facing aspect??

2. Any recommendations for rearfacing, no latch in the mountaineer?

[Joolsplus2]

Lots of people have huge problems installing the CS rearfacing, so you aren't alone there...

Try www.carseatdata.org to see if anyone has had luck with a seat in your car, and look at the Cosco Touriva or Regal Ride...it's the same seat, different covers, the T comes from walmart, the RR from target. It's not the most wonderful seat (compared to your RA! lol), but for $49, it's easy to install and light and simple to use properly. You will probably need a rolled towel or pool noodle to get it reclined, though and older RF baby who can sit more upright won't need that as long as they like to sit quite upright.

You could also look at the less expensive Evenflo seast, like the victory and titan (the Triumph is nice, but extremely bulky and heavy), some people like those just fine.

good luck! (and be sure to read both your car and seat manuals thoroughly...sometimes they offer tips for getting the seat in tight)
Julie CPS Tech and mom to 2 in seats
http://www.cpsafety.com/articles/RFAlbum/SarahMA.aspx