maintaining form post session using curl

Hello,

I have searched for a good part of the day, but cannot seem to find an answer to this. I hope this is an appropriate forum for my question.

I am wanting to download a blog web page using a script. It requires username and password login. I have tried the following (an example) to no avail:

curl -d username=username -d password=password http://siteurl/index.php

I then tried this hoping that I could get the session started and then go to the page:

curl -d username=username -d password=password --url http://siteurl/index.php --url http://siteurl/desired_page.php

and the same as above using -u username:password instead of -d

I get the pages but I am not logged in. I have tried these methods on other pages using post forms for passwords and it works fine. I have checked to the source of the login pages and I am using the correct name values for password and username. I am trying to download pages that are privy only to members, and I cannot download them

I don't believe the site is using cookies to remember my login info for a session because when I log in and out using firefox, my cookie list does not change.

Does anyone have any ideas what is happing with this?

update ( this is not a bump - I just discovered some new information )

I noticed that I can create a dummy html login page with just a form where I submit the same information, and can log into the index page just fine.

I cannot understand then why what I have tried using curl does not work, since it works on other sites I have tried it on.

I double checked the names and values and they are correct.