Imported From: http://groups.google.com/group/in-portal-bugs/browse_thread/thread/9db1d82d9f67141a#
There is a special feature in In-Portal (that I bet nobody knew about) that
allows each system setting have it's own validation logic, e.g. be always
required or allow only numbers.
To use it you need to place serialized array of field validation options
into "Validation" column of that system setting.
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