Change SDP settings to a specific address

[sympology]

1. Brekeke Product Name and Version:
SIP Server 3.1.7.0 Advanced Edition

2. Java version:
1.7.0.15

3. OS type and the version:
Win 2008 STD

4. UA (phone), gateway or other hardware/software involved:
Aastra, TeleVantage 3rd party SIP Trunk

5. Your problem:
I'm having trouble establishing calls to our provider (we have connectivity). The problem is they will only accept call that appear to originate from the SIP Proxy. Part of the issue is the 3rd party may appear to be a non-remote address as it's on a private wan extension.
I need to change the from header in my sessions.

Summary:
PBX = 10.x.x.x/8 (we have multiple PBX's)
BSS = 10.32.84.15
Provider = 10.32.250.50

When I make a call the SDP to the provider, wireshark shows the "From" header as "user"@10.x.x.x and I need all session data to be "user"@10.32.84.15
However I need all traffic NOT destined to 10.32.250.50 to remain untouched as we used it for a heck of a lot of internal call routing.
I've tried everything I can think of, but no doubt I'm missing something really obvious.

Thanks,
stu.

[ambrosio]

Do you have any DialPlan rules which point the provider's IP address 10.32.250.50?

If not, try the rule like the following.

[Matching Patterns]
$request = ^INVITE
From = sip:(.+)@
To = @10.32.250.50

[Deploy Patterns]
From = sip:%1@10.32.84.15
$continue = ture

[sympology]

Thanks,
I did that but still didn't work, so battled through and changed every fieild I could find referencing the call orginator and still no joy. I've passed it back to the SIP provider as I've a feelign it's an issue at their end.
Thanks for you help, I may be back!

[ambrosio]

Can you paste an INVITE packet here?

If so I might suggest another dialplan rule..