TBC Macros and Extensions

I'm writing an IronPython macro to read/edit pipeline weld-point data that's visible in TBC's GIS ribbon > Pipeline Attributes > Load data into Excel, but I can't find the underlying object model for it.

Confirmed structure, from the source .jxl (product="Trimble Pipelines", productVersion 25.20): each surveyed point carries a CustomXmlSubRecord (Creator: Pipelines_v2.00.092.0) containing:

PipelineData
  JointData (x2 - one per JOINT_BEHIND, one per JOINT_AHEAD)
    TallyItem: Name=JOINT_ID, Value=...
    TallyItem: Name=HEAT #, Value=...
    TallyItem: Name=JOINT LENGTH, Value=...
    ...

There's also a companion CustomTypeRecord/CustomEntityRecord pair (TypeName=TallyFile) that maps this back to an external "Pipe Tally" CSV the field crew referenced (UniqueJointID, JointLengthID, JointBehindID, JointAheadID fields).

Once imported into TBC, this same data is visible in a point's Properties pane under a separate "Extended Attributes" section (distinct from the plain "Feature Attributes" section), and includes JointID, TallyLength, CalculatedLength, InversePoint, AlignmentName, Station, Offset alongside the JOINT_BEHIND:/JOINT_AHEAD: fields.

What I've ruled out from a macro, with confirmed results (not just guesses):

• SnapInAttributeExtension.UserAttributes.Overloads[ISnapIn](point) - runs clean, returns other per-entity data, but none of these fields.
• Same call against each associated Feature object - same result, empty for these fields.
• UserDefinedAttributes via project.Lookup(27) → .GetAssociatedAttributes(serialNumber) (the pattern several published macros use for 12d-import attribute blobs) - the object itself works correctly (raises a proper KeyNotFoundException for a wrong key), but holds zero keys for these points.

Question: Where does TBC store the imported CustomXmlSubRecord/PipelineData content after a Trimble Pipelines jxl import, and what's the macro-accessible class/namespace for it? A pointer to the right namespace - even without full documentation - would be enough to get started.

I'm unfamiliar with the Access Pipeline module. I'd need to see the TBC data directly to inspect/understand the underlying object structure.

Can you please upload a few points as VCL file here or send it to my email address r.schneider.eu@gmail.com.

Try looking at 

RDPoint.PipelineData in Trimble.Vce.Data.RawData (Assembly Trimble.Sdk.RawData)