Are you people daft?! What do you not understand about Xbox Live Silver members not counting for the Call to Arms promotion. The promotion ends March 1st. Xbox Live Silver members do not have access to the demo until March 1st, one week after Gold.
Copy & Paste from
http://dragonage.bioware.com/da2/demo/
"February 22, 2011 marks the launch of the Dragon Age II Demo and a Call to Arms for all BioWare fans. We are actively recruiting an army of Champions, and if we get over 1 million demo downloads and logins on the PC, Xbox 360 and PS3 combined before March 1st, we will unlock two in-game items for the entire community to use in Dragon Age II. Demo download progress will be tracked on this page, so check back often!"
"*Offer expires March 1, 2011. Requires Internet connection, EA account, ownership of Dragon Age II ("Product") for the Xbox 360, PlayStation 3 or PC. The Demo must be downloaded by 1 million users across the Xbox 360, PlayStation 3 and PC for the items to become available. EA online Privacy Policy and Terms of Service are available at www.ea.com. Must be 13+ to create an EA account. Valid everywhere Product is sold. To access items in the Product , you must be logged into the Product using the same EA account that you used to register your Product and 1 million users must have downloaded the Demo within the time period specified. Items are nontransferable. May not be combined with any other offer, gift card, rebate or discount coupon. Void where prohibited, taxed or restricted by law."
So best case scenario is that Xbox Live Silver member downloads made on March 1st will count toward the 1 million.