ERWin - Changing date to datetime

If you are using ERWin 2.6, you may be able to help me... I am connecting to an Informix database (7.14) using ERWin to do all of my updates to the database. When I first created this database, I used the date datatype for all my date columns. Now I want to change them all to "datetime year to minute". The problem is I only get "datetime <large> to <small>" in my DDL and must be edited before updating the database. Is there a way to set the large and small variables so that I get the correct entry into the statements. Thanx