Amit,

  Could you try to do it in an activity while creating the Service object? There you might have two steps, first create a page of class Data-WorkAttach-File. Copy the Attachment from Interaction object to it. Similarly open the Link-Attachment record with the Interaction object id. For your newly created attachment page, create a Link object using the activity method Link-Objects. After that save and commit the Service case. It might work.

Hi Amit, For each attachment records that are stored in the attachment table are linked with the work object id, so whenever we are want attachments of any othwr work item in current work item, we can use obj-browse and in condition use contains with the other work object id.