fcpxml asset-clip "tcFormat" attribute question

I'm trying to create code to generate an fcpxml file so I can automate Final Cut Pro timeline (project) creation. Here's an xml element that FCP successfully imports (and successfully creates a project/timeline).

<project name="2013-08-09 19_23_07 (id).mov">
    <sequence format="r1">
        <spine>
	<asset-clip ref="r2" offset="0s" name="2013-08-09 19_23_07 (id).mov" start="146173027/60000s" duration="871871/60000s" tcFormat="DF" audioRole="dialogue"></asset-clip>
        </spine>
    </sequence>
</project>

The xml element example above was generated by exporting a simple timeline with a single clip. The problem I'm having is the media asset has timecode that gives a start time in relation to the timecode. When I try to remove timecode attributes and change the start time to "0s"

	<asset-clip ref="r2" offset="0s" name="2013-08-09 19_23_07 (id).mov" start="0s" duration="871871/60000s" audioRole="dialogue"></asset-clip>

FCP complains with the import error:

2013-08-09 19_23_07 (id).fcpxml Invalid edit with no respective media. (/fcpxml[1]/project[1]/sequence[1]/spine[1]/asset-clip[1])

I guess the question is, does AVAsset provide a way to get the timecode information and the timecode based start offset, or is there a way to tell FCP to use a default start time independent of timecode?

fcpxml asset-clip "tcFormat" attribute question
 
 
Q