Informix CLI vs Informix ESQL/C

To All, We are developing a gateway to Informix which within one process must support several clients at the same time. We have prototyped this project and found that on NT and HP-UX that both client API's (ESQL/C and CLI) appear to block. In the CLI; which is really ODBC I set the connect options and the statement options to SQL_ASYNCH_ENABLE in hopes of creating a non-blocking connection to the Informix database. To no avail my execution of SQLExecute() or SQLExecDirect() still blocks. In other words I do NOT recieve immediate control. In ODBC if the driver supports it I could do SQLExecute() and test for SQL_SUCCESS or SQL_STILL_EXECUTING. If I got the still executing response then I could go off and do other work comming back to this later to see if it was done. Essentially a non-blocking client api. In a non-threaded environment this is imperative for multiple clients through one process. My question is: Has anyone successfuly used ESQL/C or Informix CLI in a non-blocking mode? Informix Technical Support has not answered this question. Thanks for your help, Ken Crismon