Account Search Problem (subaccount), Help pls!

It appears we can't search accounts by acctname if "the account" is a sub account of other accounts.

let's say we have 2 accounts:
1) 1000 Sales
2) 1001 Sales - Fuel (sub account of 1000 Sales)

I code something like the following:

            Dim coaSearch As New AccountSearch              Dim coaSearchBasic As New AccountSearchBasic              With coaSearchBasic                  .name = New SearchStringField()                  .name.operatorSpecified = True                  .name.operator = SearchStringFieldOperator.is                  .name.searchValue = "Sales - Fuel"                    .number = New SearchStringField()                  .number.operatorSpecified = True                  .number.operator = SearchStringFieldOperator.is                  .number.searchValue = "1001"              End With              coaSearch.basic = coaSearchBasic              Dim rr As SearchResult = Me.NsService.search(coaSearch)              If rr.status.isSuccess Then                  rr.recordList.Length = 0   ?????              end if

The end result is not what i expected, if i search by acctnumber, i got one result;if by acctname, zero.