Interplay Websevices API provides functionality to create a placeholder masterclip (offline masterclip)

The documentation says only "batch capture" is supported to bind media to a placeholder or offlne clip. Tapes are used way less these days and most ingests are file based now.
How can I, by using Media Central Ingest API, add file based media to the placeholder masterclip in MediaCentral Production?

I know this is a pretty old question, and maybe you figured it out already... but anyway.

If you create a masterclip (AAF) which which references some source mobids, then the interplay environment will (using dynamic relink) find clips that have the same mobids anywhere in the indexed workspaces on shared storage. 

So in order to "add" file based media to the placeholder clip, you only need to set the same source mob id on the individual OP-Atom files (if you are using MediaProcessor (AMT 3.0) you can set source mob id using its API).

Be aware that also timecode needs to match. If you create a masterclip that references some nonexistant start time and duration, then media will be offline even if the source mobids match.