I am using the SDK, but I can't find how to filter by KEY use ID and/or KEY and it tells me that it is not possible
Dim m_salesList = oCompanyContext.Factories.SalesInvoiceFactory.List()
oFilterFact = FilterExpression.Equal(FilterExpression.Property("SalesInvoice.ID"), FilterExpression.Constant(sID))
oModifiers.Filters = oFilterFact
" Filtering or Sorting is not supported on the specified property path 'ID'"