From help pack
QuotePACK (Equipment)
This command allows your character to pack supplies, goods, armaments,
and so on, upon a beast of burden, relieving him/her of the weight and
bulk. When used without an argument, it will show you what has been packed
upon the mount.
Syntax:
pack <item> <animal - optional>
Examples:
> pack
> pack shield
> pack bag kank
Notes:
Your character must be mounted for this command to work.
Only certain types of containers can be packed; in other words, you
cannot pack a sword onto a mount's back, unless it is in a backpack,
bag, or some other container. Generally speaking, you cannot pack
water containers (e.g., waterskins) onto mounts.
See also:
mount, unpack
From a game experience:
Quotepack shield>
You can only pack a mount with containers.
was just wondering if the shield part was going to be implemented or if the helpfile could be changed.