ODBC timeouts

Hello.  I have a question about timing out queries using clsql.  I am 
connecting to a Microsoft SQL Server database via ODBC and clsql;  for 
the most part everything works just fine.  However, when the database 
crashes or shuts down (which happens more often than I would like, but 
is out of my control), strange things happen to my clsql connections. 
It seems as though the open database handles never timeout in those rare 
cases when the database has gone away.  I noticed this line in 
odbc-constants.lisp:

(defconstant $SQL_QUERY_TIMEOUT                 0)

But I don't see the timeout referenced anywhere else in the clsql code 
base.  Can someone help me out by explaining how I can cause these 
hanging queries / connections to timeout in a predictable way?  I have 
tried using sb-ext:with-timeout, but the timeout seems to never happen 
when clsql ends up in this hung state;  perhaps something to do with 
interrupts being disabled in this context?

Any ideas or pointers are appreciated.

Cheers.
Kevin Raison