Crssp

Out of the box, Revive Adserver v3.x only supports the VAST1 specifications, and it does not have support for creating pre-roll ads that are essentially using VAST2 tags from third parties.
 
I would like to suggest having a look at the Advanced Video Ads plugin that you can find here:
http://www.adserverplugins.com/advanced-video-ads-plugin-for-revive-adserver/
 
This plugin will enable you to traffic a third party VAST2 tag (we call this a Network Video Ad) as a banner, and then to serve that into any VAST2 compliant video player.

Full disclosure: this product has been developed and is being sold by my company.

Getting the PreRoll Adzone for VAST with Revive Adserver
 
1.)  Create the Zone in Revive Adserver � NOTE YOU CANNOT SEE THE ADZONE yet
2.)  Create a Campaign and link to the zone
3.)  Create a Banner ad for this campaign
4.)  Select the zone to place the ad into and Document the ID  which in my case is 20
5.)  Script to add to the player
a.     http://{yourdomain.com}/{youradserverfolder}/www/delivery/fc.php?script=bannerTypeHtml:vastInlineBannerTypeHtml:vastInlineHtml&zones=pre-roll0-0%3D20&nz=1&source=&r=R0.023106331005692482&block=1&format=vast&charset=UTF-8
b.     Where the D20 is located in the script, change the 20 to the ID in Revive
 

What you're looking for is not IAB VAST compliant video ads provided by the bundled plugin, as they are more like what you see on YouTube: commercials before/after actual content videos and overlays. That's also what our VidiX plugin is about.
 
What you're looking for is a regular banner that shows a video, which is something we can also provide by means of the In-Banner Video Ads plugin.
 
Otherwise, a quick (and free) solution would be to put your HTML5 video code in a regular HTML banner and serve it on the website like any other banner.

Revive Adserver (like its predecessor OpenX Source) comes bundled with a plugin that enables it to deliver video ads based on the VAST standard. This VAST standard has since been replaced by the VAST2 and recently even the VAST2 specs. VAST is short for Video Ad Serving Template, it's a set of specifications issued by the IAB (Interactive Advertising Bureau), an industry standards body.
 
The site mentioned by leroy_hack (who comes up with those odd names?) is a project started in 2009 by my partner Matteo Beccati and myself. We develop free and paid plugins, and one of them is called VidiX. It bumps up the VAST capabilities of OpenX Source and Revive Adserver to the VAST2 specifications. Please be aware that it is not a free plugin.

Yep, HTML banner with wildcard sizes would be my first suggestion!

Hi @Crssp,
Welcome! This is a complex topic, and I'm actually working on some more documentation to try and explain better how Revive Adserver decides which banner to display for a zone, and after that, I probably need some better documentation on how it calculates priorities.
However, in the meantime, here are some thoughts that may help:
You say that when you go to view the probabilities for Zone 2, it says that there is a 95% chance of showing the remnant ad, and a 2.5% chance each of showing the two links contract ads. Is that wrong? You don't provide any details of how many impressions that zone is delivering per month - perhaps 2.5% of the zone impressions is, in fact, all that is needed to get to 25k impressions? However, I suspect that's not the case, because you're talking about a test setup, so I doubt you are putting "live" levels of impressions through your test setup. In that case, what you may be seeing is "slow start" to campaigns - newly created campaigns are deliberately set to have a low priority level, just when they are created, to help try and ensure that they don't blow through your entire campaign budget in the first hour. You can certainly move away from contract campaigns to remnant, to get a more even distribution, but it depends what you want - an even distribution, or the delivery pf a target number of impressions! Hope that helps.