I'm not sure how to do that...maybe try posting your question in the Access Forum, however insteading of importing the data, why don't you link the table(
Open Access
File>Get External Data>Link Table...
Select ODBC Database()
Select the File Data Source
Select the relevent Table(s))
to Access, and then create a query in Access to get the Data you want. (to query will run against the Data in Informix)
Another option could be to create some VBA code to connects to Informix DB and then queries the DB and insert the Result set into Access.
for example...I have a Oracle DB, however I need to import some reporting data into Access.. So when I click a button (Create Monthly Report) it performs the following.
1. Connects via odbc to Oracle
2. Runs a Select queries against the oracle tables
3. inserts the data into the Access table
4. produces report.