Publishing Air from Flash CS4 generates error connecting timestamping server.

I am using Comodo digital signature which apparently requires to change the default  timestamping server URL. How do I do that? Is there a way to change the air setting interface of Flash CS4  to point to a specific timestamping URL? Are other ways around it? I know i can disable the timestamping, but that creates  it's own expiry problems.

Thanks

Joseph Karov