We must had released a modified version of Zasilkovna for Virtuemart 3 to support latest VM code and to be able to optimize the code for OPC display. Zasilkovna can be installed from OPC Extensions tab within OPC backend.
Update January 2017:
No modifiations are needed to Zasilkovna plugin to use it with our OPC since Zasilkovna had merged our suggestions to their Github official version. You can download official and the latest Zasilkovna plugin from here:
https://github.com/Zasilkovna/virtuemart3
Click clone and download + Download ZIP + Install with Joomla installer
Legacy information
Zasilkovna for Virtuemart is a branch shipping method which displayes address details of the branch where the pickup will occur. OPC zasilkovna does not (yet) supports printing of the labels or other advanced features - please use the original plugin for this purpose supplied by the zasilkovna.cz