Windows / .NET :: Return String From Oracle Stored Procedure Using Excel 2003 VBA

I am trying to return a value of an oracle stored procedure using Excel VBA.

OS: Win XP SP3
Excel 2003
Ora Client: 11g

By trying different things I have noticed, that I could have troubles with the ODBC-connection. Maybe I am not using the right one. To store data returned from select statements I have an ODBC-Connection (Driver: Oracle in XE), which works perfectly, e.g.:

'-----------------------
Sub Extract_Data()
Dim cn As ADODB.Connection
Dim rs As ADODB.Recordset
Dim db_name, UserName, Password As String
cn.Open db_name, USerName, Password

[code]....

When debugging the connection string, I find the Provider=MSDASQL5.1.