I created a tremolo effect using the VS. It is made using the dual compressor/limiter effect (not the stereo-multi effect which also has 2 compressors). It requires a click track as the sync device for the tremolo's speed. The advantage of using a click track is you can lock the tremolo's speed with the tempo of the song even if the tempo of the drums wanders.  Removing sections of the click track will have the effect of turning the tremolo off and on. The click track can be erased after the tremolo track is recorded so it won't permanently use up a track. 

The idea is to use the click track as a sidechain signal to compress the guitar track. Each click will lower the guitar's volume briefly. Playing with the "threshold" and "ratio" setting will determine the depth of the tremolo. Playing with the "attack" and "release" settings combined,  will change the shape of the envelope and the timing (not the tempo) of the envelope. The tempo is set by the click track, but the attack and release can delay the onset of the volume reduction and increase. 

To set it up, I will use the example requiring track 1 as the click track and track 2 as the instrument with the tremolo effect. Input 2 will feed track 2.

Record a click track on track 1. Each click will represent the peak of the trem volume. Use short sharp clicks like clicking two drum sticks together. The clicks should peak near 0 dB fs. (In other words as loud as possible without clipping too much.) If it clips a little it's not real critical.

Route the instrument (guitar etc) through input 2 to track 2. 

Insert the dual/comp/limiter effect into track 1 as "insert L". Keep track 1 fader at zero. (The click signal will still go to the effect unit.)

Insert the same dual/comp/limiter effect into input 2 as "insert R". Route input 2 to track 2 as you would normally.

Now go to the dual/comp/limiter effect's edit screen.  Input A is the left channel (click track). Input B is the right channel (guitar signal).
 
Go through the edit screens and set them as follows:
Turn off compressor A. 
Turn off noise suppressor A.
Turn off noise suppressor B.
Turn on compressor B.

These are the settings I used for a medium-slow tempo song with the click track on eighth-notes (trem oscillations on eight notes).
Set the compressor B page as follows:
Threshold: -36 db
Ratio: 100:1    (this gives a pretty deep trem)
Attck: 50
Release: Around 15
Detect: A (this selects the click as the control signal for compressor B)
level: 0 (This really should not be above zero because the extra gain could cause clipping. You should be able to get decent volume by changing the shape of the envelope using attack and release.)

Now, when you listen to the guitar while the click track is playing, you should hear the tremolo effect.

Syncing tip: 
When you are setting up the envelope (the feel of the tremolo), you will play with the attack and release times. This may effect the syncing of the tremelo with the drums. The tremelo may sound to be lagging or leading the drums. To fix this you "track insert" a tiny blank spot at the beginning of the click track to get the trem synced with the eighth-notes. I found it only takes a few frames to accomplish this. I added 4 frames to the beginning of the click track to get it synced. Getting it synced should be the last step. Play with the attack and release to get a good sound. Turn the drums off when auditioning the trem sound. This way the sync won't effect your judgment of how the trem sounds. Worry about the sync later, after you are satisfied with the trem sound.