1. Start any multiplayer mission using the new Respawn Screen and Curator (ZGM Master Altis 48 +2 as an example).
2. Join the game in a Curator slot. On ZGM Master Altis 48 +2 this appears labelled "Game Master". This usually appears under the Virtual Units faction.
3. Place a Loadouts module. This usually appears under the Respawn tree menu under the Modules tab. The Modules tab icon is three boxes stacked in a sort of triangle. The Loadouts module may be selected by left-clicking on the word "Loadouts" under the Respawn tree menu. This is usually found beside an icon showing an AR15-type rifle with three magazines underneath. Magazines are boxes that hold cartridges used for rifles.
4. Wait for the Loadouts module dialog to appear.
5. Select any saved loadout created using Virtual Arsenal. These usually appear under the Arsenal tree on the dialog.
6. Return to the lobby and join as a player in any non-Curator slot. This is usually accomplished by going to the pause menu (binded to Esc by default), and selecting abort, then selecting OK from the dialog box that appears. The Esc button may be found on the top-left corner of most US QWERTY keyboards. Alternatively have a friend or other third-party join the mission in a non-Curator slot.
7. When the player who is not in a Curator slot, be it a third-party or oneself, finishes loading, the new Respawn Screen should appear. Attempt to locate the aforementioned Virtual Arsenal loadout under the Role list box and/or the Loadout list box. It will not appear. This is a bug.

The following may help you in locating UI elements which may have confusing names such as "list box" or "tree menu":
http://images.akamai.steamusercontent.com/ugc/55484619582118393/2DD1E84FC567846672B305BD17DB474F61740F28/?interpolation=lanczos-none&output-format=jpeg&output-quality=95&fit=inside%7C637:358&composite-to=*,*%7C637:358&background-color=black

A "list box" is the 6th UI element on the 1st column of the image.
A "tree menu" is the 2nd UI element on the 2nd column of the image.

Many of the steps above require you to left-click on UI elements. It may be advisable to use a mouse to accomplish this.

For clarification, this is what a magazine looks like:
http://vignette3.wikia.nocookie.net/fallout/images/3/3e/Assault_carbine_extended_magazines.png/revision/latest?cb=20110207025854