If you're using WSI you can do that with the Display node under the entity:
Code:
<Display>
<XmlPackage></XmlPackage>
<ColWidth></ColWidth>
<PageSize></PageSize>
<SkinID></SkinID>
<TemplateName></TemplateName>
</Display>
In the older XML import method, you would use the XmlPackage node.
Code:
<Category>
<Name>Category 1</Name>
<ParentCategory></ParentCategory>
<Summary></Summary>
<Description></Description>
<SEKeywords></SEKeywords>
<SEDescription></SEDescription>
<SETitle></SETitle>
<XmlPackage></XmlPackage>
<ColWidth>4</ColWidth>
<DisplayOrder>1</DisplayOrder>
<Published>1</Published>
<ImageFilenameOverride></ImageFilenameOverride>
</Category>