All custom charting plug-ins have been successfully tested and are confirmed to work with PlayOnMac (and PlayOnLinux) with WINE 1.8-staging (or later version).
After you install MT4 and have it working with PlayOnMac/PlayOnLinux, you need to go to your PlayOnMac configuration, choose Metatrader_4_ virtual drive and go to "Install components".
From the available component list, select and install "dotnet40"
Once installed, go to "install application" in PlayOnMac, choose "Manual Installation" and make sure that you choose "Edit or update an existing application" to install the plug-in to the same virtual drive as MT4.
When you see a window telling you "Please choose a program", you need to check the "Show virtual drives" checkbox and select "MetaTrader_4_".
Select and install the custom charting plug-in of your choice (Median Renko, Renko, RenageBars or PointO).
When prompted to "Repair .NET 4.0", just close the .NET4 installation window, as you already installed this as "dotnet40".
When the installation is complete, you can start MT4 and use the plug-in.
Remember to enable DLL calls in MT4.
Here is a video showing the installation procedure using PlayOnLinux on Ubuntu with the latest version of WINE: