Question

I installed a demo of miku V4 but the plug-in but doesn't appear on the list of instruments. I also tried to install a later version of piapro studio with the same result. I'm using windows 8

Answer 1

Third Party VST integration is not supported with Studio One Prime. In order to be able to utilize additional plugins, you would need to either upgrade to Studio One 3 Professional or upgrade to Studio One 3 Artist version and purchase the VST/ReWire Add-On; which allows for the use of additional non-bundled Third Party VSTs as well as adding ReWire Support in Artist

--> IMPORTANT INFORMATION: Here is a Studio One 3 Version chart breakdown of what features are included in each version of Studio One 3. It is VERY important that you read this article so you understand the limitations of EACH version of Studio One 3:
http://studioone.presonus.com/compare-versions

You can purchase the Upgrade or Add-On here:

Upgrade:

Studio One 3 Professional: https://shop.presonus.com/products/software/studio-one-prods/Studio-One-3-Digital-Downloads/Studio-One-3-Professional

Studio One 3 Artist: https://shop.presonus.com/products/software/studio-one-prods/Studio-One-3-Digital-Downloads/Studio-One-3-Artist

Add On:
https://shop.presonus.com/products/software/studio-one-prods/studio-one-add-ons/VST-and-AU-and-Rewire-Support

Artist Booster Pack Bundle:
https://shop.presonus.com/products/new-noteworthy/Artist-Booster