Creating a date field from a text value with time zone

I want to create a date/time field with a value in it. The value is available only in text format ( eg : 3/27/2009 1:15:00 PM EST). How can I store this into a date field without any zone conversion happening. If I try to use @TexToTime , it gets converted to the current users/servers time zone. I want to store the value in original time zone. Any ideas? Either script or formula solution is ok.