I think you can get this to work both with a regular Text item, or with a Credit Roll item. If this is just a single item, you might just use a single Text media generator, with keyframes, as you've attempted. If this is a long list of credits, the Credit Roll feature will probably be easier.

First, to address the problems you have with the text item starting over. All generated media items, like Text and Credit Rolls, have a time (length) associated with them. If you manually stretch an event out, you might notice a little, triangular notch in the event. This shows where you've reached the natural end of the event. Unless you specify otherwise, VMS's normal course of action is to "loop" or repeat the event.

For example, if you have a text item that is 5 seconds long, and you stretch it out to 7 seconds, you will see a little notch at 5 seconds. VMS will restart the event at that point, and show the first 2 seconds over again. If you want the event to "freeze" at the end, rather than repeat, simply right-click on the event, select "Switches", and uncheck the "Loop" setting. Now, when VMS hits the end of the event at 5 seconds, it will just freeze there, rather than repeat at the beginning. This is true for a regular video clip as well.

However, the problem you are having is that you can't move your keyframes out as far as you would like. This is because you actually need a 7 second event (for example), not a 5-second event stretched out by 2 extra seconds.

Locate the Text item you want to change, and click on the little green "Generated Media.." icon on top of it (looks like a little film frame). At the top of the window that pops up you will see Frame Size (720x480), followed by "Length 0:00:05.00". Change this to 7 seconds, for example, and now you will be able to move your keyframes out to 7 seconds. Also, the "notch" will move or disappear from your event.

If you need to do many of these, I would encourage you to check out the Credit Roll media generator. I just tried it out about a week ago, but it seems pretty powerful.

Drag a Credit Roll from the Media Generators window onto your timeline, and open up the Video Event FX window for it (click "film frame" icon). In your case, it sounds like you want a "Timed Sequence" rather than a "Scrolling Credits" (See the Properties tab at the right side of the window). If you select Timed Sequence, you can then specify "In = Enter from Bottom", "Out = Exit to Top". In between the enter and exit activity, the text just sits still.

On the Credit Roll media, the time that each item stays on the screen is dependent on how long the overall event is, and how many sets of things you have to display. If you've defined three sets of things to display, and your event is 12 seconds, then each item gets 4 seconds. This would include the entry and exit times, I guess.

I hope this helps.

Tim L