Open xml relationship target is NULL when inserting chart

Hi,

I have looked into the specification ISO/IEC 29500-1:2012 and i understand that the attribute Target for the element Relationship can be set to NULL at times(Empty header and footer in the specification).

Now, i have stumbled on Target being NULL also when inserting a diagram into a word document. For example:

<Relationship Id="rId3" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/oleObject"Target="NULL" TargetMode="External" xmlns="http://schemas.openxmlformats.org/package/2006/relationships" />

I'm using Open xml sdk and i'm trying to create a relationship. My question is how i should resolve the target which i think should point to the diagram/chart that i inserted.

Br,

/Peter

Peter