i think the OP understands that and is trying to map a syntakt parameter to a external controller. (on the fx track its on page 2 of filter tab, controlled with encoder E ) . the external controller needs the relevant midi cc / nrpn from the syntakt manual … not the other way around …
fx track midi cc’s are on page 118 in the syntakt manual , but no ‘filter pan’ midi cc is in the chart for the filter secion …
I’d assume as its a new parameter , either there is no midi cc or it hasnt been updated in the manual yet (or both)
its also missing from the LFO destination list for fx track filter section but it is in the actual list of destinatioins on the device (so the manual is basically out of date)