Found it after looking into Excel attachments :
'Create a modeldescriptor to the Pro/E Model
Dim oModelDescriptorCreate As New CCpfcModelDescriptor
Dim oModelDescriptor As IpfcModelDescriptor
Set oModelDescriptor = oModelDescriptorCreate.Create(EpfcMDL_PART, sNumber, Null)
'Retrieve the model into the oModel handle
Set model = gSession.RetrieveModel(oModelDescriptor)
'Create a new window which displays the Pro/E Model
Dim oWindow As pfcls.IpfcWindow
Set oWindow = gSession.OpenFile(oModelDescriptor)
'Activate the new window
oWindow.Activate