i'm trying to mass delete our opportunities using web services, and i'm getting the "This transaction cannot be deleted because it is linked to by one or more transactions" error.  so, what i'm doing is doing a transaction search, using the internal ID of the opportunity that i'm trying to delete to get its linked transactions:

 WriteResponse[] deletions = _service.deleteList(opportunityRefs);    foreach (WriteResponse delete in deletions)  {      if (!delete.status.isSuccess)      {          TransactionSearch linkedTransactions = new TransactionSearch();          TransactionSearchBasic basicTrans = new TransactionSearchBasic();            SearchMultiSelectField oppSearch = new SearchMultiSelectField();          oppSearch.@operator = SearchMultiSelectFieldOperator.anyOf;          oppSearch.operatorSpecified = true;          oppSearch.searchValue = new RecordRef[] { (RecordRef)delete.baseRef };            basicTrans.opportunity = oppSearch;          linkedTransactions.basic = basicTrans;            SearchResult linkedTransResult = _service.search(linkedTransactions);            ...