How to added part models to Simple representation with J-link / vb api

I have successfully created new Simple representation vb.net. But not able to add part models to it.

Since pfcls codes for both vb and j-link will be similar. Please any one guide.

My codes are below

Dim newsimRep As IpfcSimpRep

Dim newsimRepInstrs As IpfcCreateNewSimpRepInstructions

Dim newrepname as string="Fix"

Dim solid As IpfcSolid

Dim simRepItem As IpfcSimpRepItem

newsimRepInstrs= (New CCpfcCreateNewSimpRepInstructions).Create(newrepname)

newsimRep = solid.CreateSimpRep(newsimRepInstrs)

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Now I want to add items to this simple representation

Not able to add items to simRepItem

Please guide with codes in J-link or VB.net

Thanks

Gopinath