[imp] Prepopulated value for "from_addr"

[lst_hoe01@kwsoft.de]

Hello

we try to let our users choose from a set of valid addresses for their 
"from_addr". By
default now one can only choose if the user can set the "from_addr" 
(typing something
freestyle in) or lock the from_addr to one value. Create a identity for 
every address per
preference hook seams a little bit overkill.
Therefore we want the preference "from_addr" to be a "select" type 
field and get the
values the user can choose from a DB query.
Any comments if this is possible, where we should start and if others 
maybe found this
useful?

Thanxs

Andreas