Setting up a Multi-Site with multiple domain names?

I am setting up a multi-site for http://www.dtautofinancing.com

What I need to do is have all of the vehicle listings posted on http://www.dtautofinancing.com also being listed on http://www.autocreditlinks.ca

This cross linking needs to happen automatically. Once a new vehicle listing is published on dtautofinancing.com, the listing (including all custom fields and images) need to be posted to autocreditlinks.ca without human intervention. There will be more sites like autocreditlinks.ca being setup very soon. If possible, instructions on how to setup sites that will take all of the http://www.dtautofinancing.com content would be fantastic!

I have setup the network, added the autocreditlinks.ca site (though it created autocreditlinks.dtautofinancing.com) However now I cannot access the subdomain login it has provided. Do I have to manually copy all of the wordpress files over to the subdomain? How do I map all of the content from the vehicle listings on http://www.dtautofinancing.com to autocreditlinks.ca and ensure that autocreditlinks.ca actually points to the correct site displaying all of the duplicate content. I have created WPMUDEV login account credentials, I am an absolute rookie with this stuff. My experience is primarily graphic design / branding. A friend has asked me to help him with this and I am lost! The http://www.autocreditlinks.ca site has been requested to be live today. This is unrealistic, however if anyone can help me achieve this goal I will be very grateful!

For further clarity, please ask any questions you need to. The http://www.dtautofinancing.com site is live currently. The http://www.autocreditlinks.ca has it's own wordpress install setup (currently on its' own server) that I have been trying to link into DT using RSS / Import / Export options ... to no avail. As such, I opted to try the multi-site method and now I am stuck!!

Thank you in advance for any assistance provided!

Best,

Jonathan Ellis