There is a plugin called vpnmanager which worked a treat with v7 image, even allowed the use of many multiple country vpn's. In v7 image I was using version 1.3 of the plugin but was informed that v1.6 was comaptible with openpli 8 but unfortunately it does not install successfully on the Japhar sim image.
A second vpn plugin which works successfully on openpli 8 but not on v8 Japhar sim image is called nordvpn connector which is currently on v0.4.r11.
There is obviously something in the Japhar v8 image which stops them working as compared to the original openpli image. I have attached a plugin for you to look at should you have the time and patience.