There could be a number of reasons why your plug-ins aren’t showing up in FL Studio. I haven't used ASIO4ALL in awhile but there might be a setting to change this behavior (at some risk of compatibility and latency). Designed as a light-weight sketching piano, the VS Upright No.
How to Make Electronic Music Using FL Studio Demo. This function is directly linked to the opening of saved project data and is not supported in the Trial version.
