asterisk users - Oct 2014 - SIP dialing with authentication with dialstring and wothout sip; conf

Hello,

I've got a bunch outgoing-only SIP trunks "connected" to an
asterisk 11 setup.
I've read the following doc [1] stating you can pass username/password
in a dial string.

My goal is to dial from asterisk through one SIP trunk or another
without touching my sip.conf file.

In other words, I'm planning to use:
Dial(technology/user:password at host/extension,timeout,options)

instead of
Dial(SIP/trunkname/extension)

with a sip.conf that includes something like:

[trunkname]
username=username
secret=password
host=host


My first question:
is such thing possible, for a trunk which requires a password for each
outgoing call ?

Regards



[1] http://the-asterisk-book.com/1.6/applikationen-dial.html