SQL OLEDB provider: connection string to Failover partner

We're trying to connect to SQL with Database Mirroring enabled. We have 2 servers: DB1 (Principal) and DB2 (Mirror).

We're using connection string: Provider=SQLOLEDB;Data Source=DB1;Failover Partner=DB2;Database=databasename;Uid=username;Pwd=password;

When DB1 is in principal role, everything works OK. But, when DB1 goes down, and DB2 (Mirror) becomes principal, we receive an error: "Invalid connection string attribute"

We tried to change Data Source from server name to IP, to IP:1433... without success. We also tried to change parameter "Failover Partner" to "FailoverPartner", also without success.

Is it possible to connect to DB mirror with SQLOLEDB provider at all?

Problem solved... after we moved from SQLOLEDB to SQLNCLI.