User Agent Modify in Opera

I am study how to modify the UA in Opera and it's hard to find a detail tutorial.
Most of the tutorial only said that I can use "Spoof UserAgent ID" but it only can modify as IE or FF, I want to manual typing the UA String like change from Opera to OperaMini.

It's easy to modify the UA in FF because there are "UserAgentSwitcher" add-on, it's very convenient to use.


Reference :
http://my.opera.com/community/forums/topic.dml?id=147249
http://www.opera.com/support/usingopera/operaini/#proxy


--------Add 20110425--------

Finally I know how it works!
Put the customize string in ISP:ID, than enbale the UA:AllowComponentsInUAStringComment.

==In Opera.ini===
[ISP]
Id=Opera Mobi

[User Agent]
Allow Components In UA String Comment=1
=================

It will add a additional string after the formal UA.

EX:
Default -> NG
Opera/9.80 (Windows NT 5.1; U; en) Presto/2.8.131 Version/11.10
Modify by opera:config -> NG
Opera/9.80 (Windows NT 5.1; U; Opera Mobi; en) Presto/2.8.131 Version/11.10