I use piwik and google analytics in my sites. We customize the url in piwik tag and not included the utm parameters.
When i make the same on google analytics tag i don’t have problems, google analytics categorize this traffic properly.
I have instaled plugin-AdvancedCampaignReporting but in campaign reports i don’t have traffic. For piwik tracking campaign with utm parameters is needed include this parameters on url that i customize on tag?