What SipBorker does is this:
You dial *010-123456 (which is sent as *010123456@sipbroker.com)
It knows that *010 is linked to voxalot.com, so in turn it sends the call to
123456@voxalot.com)
Assuming that you have some form of sip uri associated with your asterisk server (proxy.com or sip.proxy.com) you could add it to the SipBroker list, and it will assign it a *SipCode for your server too, it doesn't like just IPs though.
To add a SIP server to the list see here, where it says add proxy:
SIPBroker - PSTN Numbers
This is the quickest way if it works (so now people can call *YourSipCode-ExtensionInAsterisk@sipbroker.com)
Otherwise you'd have to register through e164.org, but this really only has value if you have DID numbers associated with various accounts.