Service Connect-Delete Substitute Part

I have done quite in depth few service connect projects and this one has me stumped, so i'm turning to the groups for ideas. I am trying to use service connect to delete subcontract parts in Vantage 8.03. The trace in Vantage doesn't tell me much. I tried using the Part.Update webservice with the PartSubs table RowMod='D' but nothing happens. I am all out of tricks to try and am hoping someone can help me out! Thanks