Its pretty simple, actually, you probably just lacked one tiny step from the sound of it. But for completeness sake, lets go through the full process:
You'll find the Theater View "views" in the Options under Theater View - naturally. At the bottom of the dialog all current views are available for editing, or adding new ones.
So now lets add a new one. Start off by finding the spot you want it at, in the default Layout I would suggest putting it under the "Video" main heading, in any position you like.
Click, for example, on the "Video" entry, and click the "Add" button on the right, and select "Library Item" from the dropdown.
Then make sure its positioned properly in tree, you can move it up and down, and Nest/Unnest it with the buttons on the bottom right of the tree. You want it nested under "Video", but not any deeper. It can be a bit finnicky to get the positon just right if you don't know the behavior yet.
Now that you have your fresh view, name it any way you want on the Right, and Click "Set rules for file display"
Add following rules:
- "Media Type" is "Video"
- "Media Sub Type" is "Movie"
- "Filename (path)" starts with "D:\temporary"
Basically the first two just make sure that MC knows its a movie view, this ensures it behaves like you expect.
The third rule is the one that actually controls what you need - the important part is using "starts with", because exact matches are a bit annoying to get right.
Hope this works for you. Creating such views really isn't that complicated once you get a hang for it.