I'm trying to use a link to open an xpage to a specific document based on the values on a couple of comboboxes on the initial form

The link should simply open the page with a calculated parameter documentId, which is calculated using a lookup based on the values of the comboboxes (using SSJS and doing a getdocumentbykey from a specified view).

Needless to say this just doesn't work, I've tried using getComponent("comboBox").getValue() or using the comboxes bound to a viewscope variable. The problems vary between not getting the field values or getting the field values but the documentId parameter not being added properly. I can log the fact that the lookup will work at times so there's no problem with the SSJS, but even if it finds the doc to open the link doesn't do what it's meant to do.

I suspect I'm going about it completely the wrong way. Anyone get any ideas as to how to do this in principle?