Hello,
I suppose you want to import from a non-Kentico site, right?
The content of Editable regions are stored in the CMS_Document table (the DocumentContent column) in a specific XML structure which contains a web part ID besides other properties. You are right the import tools do not support filling of Editable regions if the source site is not Kentico.
The usual approach how to import a HTML code of pages from a different source is using ASPX Templates (
Integration with your existing ASP.NET application).
Optionally, you can insert the content to Editable regions of existing documents like:
API sample.
You can also
define a new document type and insert the content to the document type fields by the mentioned import tools and display the content on the live site.
Should you need any additional details, please feel free to ask.
Best regards,
Helena Grulichova