I had posted in your German WP-Piwik forum but as you've suggested I post now here, hope my English is good enough ;-)
I use WP 3.8 and WP-Piwik network enabled. I have already made a reset and due to the mess in my Piwik installation deleted all sites; so far so good.
as soon as an old website (sub-blog) of my network is called, then the PIWIK installation created a new entry - so far so good. But this entry has for example now the (ongoing) ID 21 in PIWIK, although the WordPress ID of this blog is 1.
Problem is now, that the tracking code has also the ID 21 and not the ID 1 of the WordPress (sub)blog - and therefor I guess, the tracking is also not right?
I have created a screenshot for this dilemma:
I have tried to "create a piwik site" with in the plugin's settings, but in PIWIK itself, they get now ongoing IDs: 21, 22, 23 ...
But in this way, no single (sub)blog has in PIWIK the same ID as in WordPress - and therefor the tracking code has the PIWIK ID in it and not the WordPress ID of this blog.
I call this, what you had suggested in the forum with this code:
... this results indeed in the ID 21 - but this blog is in fact the first, that I have ever created within my WordPress network installation and has therefor the WordPress ID 1.
Is this a normal behaviour with this messed up IDs between the Piwik plugin + Piwik installation + WordPress network/multisite - and can therefor the tracking (ID) be right?
Thanks a lot in advance for any help.