Hi takme360,
I have used partial pano's ok in my TW3 Pro (ver 080609) projects so it can be done.
I'll give you an example of what I do:

I have a cylindrical 180 degree image, which I import and set the initial values on the Properties tab. I do this whilst viewing the scene (double-click the cylindrical image and set to view to "Immersive") so I get an idea of what the initial scene view will look like.
These initial values (Pan, Tilt, FOV, Speed, and Partial Pano) are important to get right. For instance: I have a 180 degree image but my FOV is 80, therefore I cannot go max-left because my FOV would require more information left of maximum than my image allows (I would need say 120 degrees of info so the image would have to be 240 degrees of view). So I reduce the initial Max/Min Pan values a little. This is not a problem for complete 360's of course.

The thumbnails also have settings similar to the scenes (Pan, Tilt, and FOV). I adjust these static settings once the scene is set to my satisfaction.

Once the scene and thumbnail are set, I can create my new movie in the time line (MovieRec tab) by copying and pasting the SlideShow timeline (- This is the system created tour based on your initial settings).
The initial values are copied across to my new time line and I can edit these to suit my purpose: Adjusting the speed of rotation by increasing or reducing the number of frames between first and last key frames. I can zoom in and zoom out - just as you can with any 360 or static image.
Single image movement (when you select a thumbnail rather than playing a movie track) is controlled by the Speed parameter on the Properties panel:
0 = no movement
100 = speed of light.
A negative value moves the image left, and a positive value moves the image right etc. I adjust these per image to get what I want.
Don't forget: This is a 180 image (-90 to 90 degrees) so I set the initial Pan setting to say -80 and speed to +10. This pans the image through the complete 180 degrees of view from left to right (minus to plus). I can go the other way if I like by reversing the values (Initial pan +80 speed -10).

Hope this helps in some way?

"This helped somewhat. But I can't seem to edit the values in the movie player. Am I to assume I need to upgrade to professional edition?"
Are you editing a new movie time line or trying to edit the SlideShow time line? The SlideShow time line is locked and cannot be edited. Copy and paste the SlideShow into a new line and make it the default.

"There's no way I can set my starting point to say 0 and have the image pan until -180? I mean, what if my client wants the scene to start at a specific point?"
Yes you can: Set 0 degrees for your start key frame, then -180 for your end key frame, and Rotation Direction "Anticlockwise".

Read on....

When you import the 180 image into TW, it is given a set of initial parameters by the program. These are seen in the Properties window. Normally, for a perfect 180 image, the initial starting point is mid-way into your image (say 0 degrees). If Initial Pan = 0, then you have 90 left and 90 right (or Pan = -90 to +90). You can set a movie key frame to start at any point and have it move around to an end point, but make sure it within the 180 pan range set by Pan Min/Max in Properties.

There's also a radio button (Panfov) which needs to be set to Partial (180).

I had the problem you describe when I set the start pan value to a value that was outside the range of the image. The result was a delay whilst the "camera" swung around to the real starting point. This could happen at the other end as well and could explain why you are getting delays?

Example:
I have a 185 degree cylindrical image: Pan initial = -139 Min = -180 Max = 5 (meaning: mid-point is -139, max left is -180 degrees, max right is 5 degrees - as set by TW - don't ask me where it get these values).
I wanted to partially pan from left to right and have set the start keyframe to -139 and end key frame to -38, with the Rotation Direction set to Clockwise (in about 15 frames). I cannot start at -180 because the FOV (80) does not allow me to see past -180 left.

Which reminds me, I must ask the forum about TS's frame rate...