Mail Merge using a doc file as data source

I currentl do a mail merge in ms word using a doc file with cell values as a data source for the merge.
Is this feature supported in aspose.words?

Thanks for your request. Could you please attach your template and sample data source for testing? I will investigate the issue and tell you how you can achieve the same using Aspose.Words.
Best regards.

insert the html file at bookmark with:

Spec_Req_Flag = processLongTextField("bmkSpecifiedRequirements", "bmkSpecifiedRequirementsCont", Path_String & "16539_6263_limit.htm", False)

which is writing into the dartemplate.doc

Thank you for additional information. If you need just insert HTML at the bookmark, you can use DocumentBuilder. See the following link to learn how to insert HTML into the document:
You can move DocumentBuilder cursor to the bookmark using DocumentBuilder.MoveToBookmark method. Follow the link to learn more:
You have attached template document (“DarTemplate.doc”), however you have not attached data source document (“DAR3src.doc”). Could you please attach this document here for testing?
Best regards.