There will be three infinite lights that cast shadows.

Add a fourth light. It will be a spotlight by default. Change it to an inifinite light.

Save the light set to the library.

Edit the .lt2 file in three places:

------------[stuff above]-------------------
.
.
.
}
camera SHADOW_CAM_LITE 4
{
storageOffset 0 0 0
objFileGeom 0 0 :Runtime:geometries:Camera:Camera.obj
}
light spotLight 1 <---- change 'spotLight 1' to 'LIGHT001'
{
storageOffset 0 0.3487 0
geomResource 7
}

camera SHADOW_CAM_LITE1
{
.
.
.
------------[stuff below]-------------------

------------[stuff above]-------------------
.
.
.
camera SHADOW_CAM_LITE 4
{
name GetStringRes(1025,18)
off
bend 1
dynamicsLock 1
hidden 0
addToMenu 1
castsShadow 1
includeInDepthCue 0
parent spotLight 1 <---- change 'spotLight 1' to 'LIGHT001'
channels
{
focal focal
{
.
.
.
------------[stuff below]-------------------

------------[stuff above]-------------------
.
.
.
smoothPolys 1
cameraModel depth
}

light spotLight 1 <---- change 'spotLight 1' to 'LIGHT001'
{
storageOffset 0 0.3487 0
geomResource 7
lightType 0
name Light 4
.
.
.
------------[stuff below]-------------------

Save the .lt2 file as a text file.

If you used Wordpad, it may have appended ".txt" to the file name. Rename the file to end in ".lt2"

Set up a simple scene. I used the ball prop and a visible ground plane.

Make sure you check Firefly and Cast Shadows in your render options.

Load your edited light set.

Arrange the lights so they should cast four distinct shadows.

Render and count the shadows.

The image is what I get using P5 SR4 on a W2K machine.

Yes, once you edit the Internal Name(s) in the .lt2 file and save back to the library, you just click on the light set as usual from then on. You don't have to edit the .lt2 file again, unless you add a light to it. You might want to rename the .lt2 file (you don't have to), or save the original somewhere, just to be safe. I used wordpad to edit the .lt2 file.