This sounds more like a configuration issue in Documentum than LiveCycle. Have your Documentum administrator check the Formats section in DA and ensure that the default format is configured for Microsoft Word for doc and docx. Interleaf appears to be a specialty software set in the publishing space from my quick Google searches.
What version of Documentum are you using? I also assume you are performing this operation using the EMC Documentum connector from Adobe?
Thanks for responding.
The doc file when uploaded manually to documentum gets uploaded as Microsoft Word format. Its only when it is uploaded from LiveCycle process then it is uploaded as some unkown format and it does not display Word icon beside the file name. If i download the livecycle uplaoded file it gives an extension of .1 or .2. But i can open it in Word.
As you said in your first post that you have tried storing document in Documentum with Document content type as "doc". Please try storing doucument with Document content type as "msw8", because in documentum this content type is associated with MS word. I hope this will work for you.