How to register Flash SIP client as 222:test@

How to register Flash SIP client as 222:test@

I rn Asterisk locally and use X-Lite , installed locally and registered to local Asterisk to dial extension numbers (local dialplans).

As a number of SIP softphone clients are Flash-based as SIP Gateways, embedded into web page
I wanted to test such Flasg to SIP Gateway to register to locally run Asterisk
as 222:test@

Do I really need to use public IP number and DDNS or alike solution to have Flash SIP client to register ?

I can download and install Flash to SIP Gateway made of SIP client and server on a local computer,
unfortunately I am not aware of any Windows based Flash 2 SIP Gateway solution.

There is Flaphone Air, stand alone Flash app (no web page embedding required),
any success story to register Flaphone Air to a local Asterisk - ?