You need a Portrait type dialog item and then need to set the size and model for it.
There are several other details you should be aware of:
Use Set Dialog Item Render Type to HDR for any Image dialog items and the Portrait dialog item to LDR to prevent the model appearing behind the image irrespective of render priority.
Setting the scale of the actor for the portrait models is near impossible so use the Invisible model and host your hero actor as a Model type actor attachment. To send actor messages to portraits you need to have a Wait For Portrait To Load action before the Send Actor Message action.
Using global actor references (::global.yourstringhere) and the Reference Set actor event action it is then possible to mark these created actors under a variable for giving them future commands.
If you pm me your email I can send you a demo map.
Rollback Post to RevisionRollBack
Contribute to the wiki (Wiki button at top of page) Considered easy altering of the unit textures?
As far as I am aware the start up screens cannot be modified. Attempting to do so will likely resulting in an account ban due to violating ToU.
If you mean to recreate something similar to the start up screen inside a map then what DrSuperEvil suggests is one approach. Another, more stupid, approach is to position actors around some area of the map, use a fixed camera viewing this area of the map and then create dialog UI elements as normal for the player to interact.