I've updated awords api to v201502 and there's a new way to create ad extensions by using CampaignExtensionSetting service.
My problem is getting an error while i'm trying to send a request with multiple operations.
[{:operator=>"SET",
:operand=>
{:campaign_id=>"284821869",
:extension_type=>"CALLOUT",
:extension_setting=>
{:platform_restrictions=>"NONE",
:extensions=>[{:feed_item_id=>"1438498066", :xsi_type=>"CalloutFeedItem"}, {:feed_item_id=>"1438490401",:xsi_type=>"CalloutFeedItem"}]}}},
{:operator=>"SET",
:operand=>
{:campaign_id=>"285081789",
:extension_type=>"CALLOUT",
:extension_setting=>
{:platform_restrictions=>"NONE",
:extensions=>
[{:feed_item_id=>"1434107755", :xsi_type=>"CalloutFeedItem"},
{:feed_item_id=>"1434268424", :xsi_type=>"CalloutFeedItem"},
{:feed_item_id=>"1434138058", :xsi_type=>"CalloutFeedItem"},
{:feed_item_id=>"1438425491", :xsi_type=>"CalloutFeedItem"},
{:feed_item_id=>"1438498066", :xsi_type=>"CalloutFeedItem"},
{:feed_item_id=>"1438490401", :xsi_type=>"CalloutFeedItem"}]}}}]