More than 256 columns in a single select.

Hi to all.
Engine 2008 R2 express on W7 pro machine.
Connection made with this Connection  String:
REMOTEDBNAME=SRL,Driver=Sql Server;Server=GIGI01\SQL2008R2;Database=SRL;LastUser=sa;UseProcForPrepare=0;AnsiNPW=No;QuotedId=No;AutoTranslate=No;Language=English

When I do a select like this
select * from master inner join detail on master.k1=detail k1 and master.k2=detail.k2
and the result set involves more than 256 columns, I get unreadable data. I tried also with 
Sql Server Native Client 10.0 but with the same issue. Driver versions are 6.01.7601.17514 for sqlsrv32.dll and  2009.100.2500.00 for sqlncli10.dll
May I try with newer versions of ODBC drivers? Where can I find it?
Many thank to all.

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