"Extraordinary units in campaign mode"

[Proelium committere]

Hello everybody,

-I haven´t found something according this problem in the faq or in other threats-

In custom battle there are some extraordinary and special units to nations, like the swabian swordsmen belonging to the h.r.e ...
And there are some non ordinary units in campaign mode, too. For example the saxon huscarls in england.

Now focusing the campaign mode, i´ve got a question.
Which are the criteria to build such units. City population? Are they mercenaries?
Example: What in hell must I do to build Knights of Santiago with Castilla?:original:

Sorry for my nasty english and greetz from germany.

[alpaca]

Most of them will be triggered by scripts (you might e.g. get them offered as mercenaries), but that doesn't work yet, so don't accept it.
There'll be more of that later.

[general maximus decimus]

So as the english I'm not yet able to build welsh bowmen, or scottish highlanders?

[alpaca]

Nay.