You need to use a custom field to do that.
Open ezEdit, got to Displayed Fields, scroll to the bottom , select one of the <Custom> fields, go to Calculated Value and add the following code in there
<a href="http://myServer/MyLocation/HelperDoc.pdf" target="_blank"><%HereGoesOneOfTheFieldsFromTheList%></a>
This would convert the field "HereGoesOneOfTheFieldsFromTheList" into a hyperlink that would open the pdf file in a new window.
Please let me know how it goes.
showed me something similar and I'm using his idea here.If it works all credit goes to him, otherwise my bad.