You sure can. :-)
OpenAjax XML is used to define the individual items which show up in the Asset Panel as well as providing rich(er) properties which appear in the HTML Attributes Panel under the Control Category.
See...
http://www.openajax.org/member/wiki/OpenAjax_Metadata_1.0_Specification_Widget_Overview
http://www.openajax.org/member/wiki/OpenAjax_Metadata_1.0_Specification_Widget_Metadata
...and...
http://www.openajax.org/member/wiki/OpenAjax_Metadata_1.0_Specification_API_Metadata_Overview
http://www.openajax.org/member/wiki/OpenAjax_Metadata_1.0_Specification_API_Metadata
For the beta release...
You can find simple examples which define items the Elements
folder in the asset panel here...
C:\Program Files (x86)\Microsoft Expression\Blend for Visual Studio\Intrinsics\
Note: The items in the \Grid subfolder illustrate how to bring along other files (in this case, CSS files).
...and you can find complex examples which define items in the Windows Library for Javascript
folder in the asset panel and the properties in the HTML Attributes panel here...
C:\Program Files (x86)\Microsoft SDKs\Windows\v8.0\ExtensionSDKs\Microsoft.WinJS\0.6\DesignTime\Debug\Neutral\Microsoft.WinJS.0.6\js\metadata\
I'm afraid we haven't yet generated the intermediate example just yet -- will probably have that available sometime between now and RTM.
Hope this helps -- let us know if you have any follow up questions.
Charlie Owen
Microsoft
charlieo@microsoft.com
