LinkedIn Integration - capturing Ad ID value information

Hi, 

We have LinkedIn Integration with Marketo that works well overall except for the one value that is not passing through - "Ad Id". This is a critical value for the PPC team as it shows from which specific banner in LI the lead came from (the form is the same for all options). 
LI support told us this is a metadata and it cannot be passed through as other form values unless you export the report from LI and import in Marketo manually. Has anyone been in the similar situation? Alternative ways of getting this data? Thanks