Using a temp table in a factbox

I'm not sure if I'm going down the right road, but what I'm attempting to do is add a Factbox to the Sales Order page in NAV 2017 based on which Sales Line is focused on. This Factbox needs to summarize the Quantities from the Bin Content table by matching the Item, Location Code, and Unit of Measure fields from the Sales Line. I've tried a few things and ended up trying to set the new Factbox up with the Bin Content table as the source, and set the SourceTableTemporary property to Yes. I then created a new local function (InitTempTable) that tries to populate the temp table using the SubPageLink that is set in Page 42 and calling it from the OnOpenPage trigger in the new Factbox. In Page 42 I am using using the same ProviderID used by the Sales Line Factbox, and a different SubPageView and SubPageLink. I was hoping that the SubPageLink would send in a filter set to my new Factbox, but alas no. The Factbox shows nothing. The debugger shows that there are no filters set at all there. I can't use a trigger in Page 42 (or can I somehow?) because I can't find a trigger with the Name defined for the Factbox Page in Page 42. Am I missing something obvious? Or even not so obvious? Any help would be appreciated!