[Zope] SQLForms and DEC()

I create a mysql table using SQLForms. Everything is fine, except one problem: I'd like to create a field as decimal(7,2). But in SQLForms I have only the choice of INT or FLOAT. When I try FLOAT, the input of e.g. 375.5 or 375,5 gives me this error message: Error Type: TypeError Error Value: not enough arguments; expected 3, got 2 The same I get if I create the table by hand using field type decimal(7,2). Does anybody know what the problem is?