The only way to add a navigation link in Microsoft Dynamics CRM 4.0 is to edit the xml to add a node. In Microsoft Dynamics CRM 2011, in addition to messing with the xml, the form ui can be used to modify the navigation pane. But if you want to enable the PassParams option, you will still need to export the solution, manually edit the customizations.xml file, zip it up and reimport.
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