[asterisk-users] @-sign gets transmitted as %40 in outgoing SIP packets (CallerID)

[Markus]

Hi list,

I'm using Asterisk 11.25.0 and would like to set 
"anonymous at anonymous.invalid" as outgoing caller ID via SIP:

Set(CALLERID(num)=anonymous at anonymous.invalid)

However, when I look at the outgoing packet with tcpdump I see that the 
@ is not being transmitted correctly:

From: <sip:anonymous%40anonymous.invalid at x.x.x.x>;tag=as26264e65

My question is how can I get Asterisk to send a "@" instead of "%40"?

Thank you!
Markus