AutoCAD Inventor :: Accessing Features From A Part In An Assembly

I'm crating a macro wich would allow me to select multiple parts in an assembly and then calculate the length of each part. The parts are tubes wich are made of a sinlge sweep.

I started from the example truesweeplength, and built from there.

Now my problem is accessing the sweepfeature from the assembly.

In the part enviroment i use this:

Dim oDoc As PartDocument
Dim oDef As PartComponentDefinition
Dim osweepcount As Long  
Set oDoc = ThisApplication.ActiveDocument
Set oDef = oDoc.ComponentDefinition
osweepcount = oDef.Features.SweepFeatures.Count

The sweepcount is simply to check how many sweep features are in the part.

This works fine in part level.Now from assembly level I first create an obecjtcollection from all the parts I selected

Set oOccurrences = ThisApplication.TransientObjects.CreateObjectCollection

Then I try to acces the first occurence

oDoc.SelectSet.Item(1)

But then I'm stuck. I cant find the way to acess the features of the selected part.