How to Change Sorting Criteria

Imported From: http://groups.google.com/group/in-portal-dev/browse_thread/thread/b73ee47c0c03ea53#

Hello,

in sorting.elm.tpl we have this type of criteria for dropdown selector:

<option value="CreatedOn|asc" <inp2:n_SortingSelected
sorting="CreatedOn|asc" selected='selected="selected"'/>> <inp2:m_Phrase
label="lu_RecentToOld"/></option>

How can we use custom fields to have our own criteria here?

thanks
p