How are you loading the VST's ?

Did you use the 'add VST' in the synth port dropdowns?

Gotta assign a track to a VSTi synth by clicking the little arrow beside track number,
then selecting 'Edit VSTi'
Then use dropdown to scroll to bottom of the scrolldown where it says 'add VST'
navigate to the folder containing the .dll file
once installed they will be there in the list next time

.. unless you've already got them into the list once

if they are already available you should be able to assign a track to one of the 16 softsynth ports, then select a synth for that port by right-clicking the track name area. This is how to assign various softsynths to different tracks

I do not work here, but the benefits are still awesome
Make your sound your own!