configuring VOIP on Mikrotik RB2011

Hi,
I have a nextiva IP phone system. I need to setup my Mikrotik RB2011 wireless router to handle this IP phone system. The only set of instructions that nextiva has is for the Sonicwall router. I have disabled the SIP but have not been able to complete the rest of the configuration. I will post the set of instructions from nextiva. Any help would be appreciated.
Thanks

SIP ALG And Multicast
Within SonicWALL products SIP ALG is called SIP Transformations. To disable it, follow the steps below.

  1. Log in to the SonicWALL device through a web browser.

  2. Select the VoIP tab.

  3. Select the Settings tab.

  4. Enable the checkbox that says Enable Consistent NAT.

  5. Disable the checkbox that says Enable SIP Transformations.

  6. • Go to the Firewall Settings tab, and select Multicast.

  7. • Ensure that the Enable Multicast checkbox is checked and that the Enable reception of all multicast addresses radio button is selected. Ensure that the IGMP Membership box is NOT checked.
    Firewall Settings
    In order to ensure that there will be no conflicts with firewall rules or settings within the SonicWALL what Nextiva requests is for them to set up two access rules to allow all signalling from our servers, and then to allow all traffic to our servers. In order to set this up, follow the steps below.

  8. Log in to the SonicWALL device through a web browser.

  9. Select the Firewall tab.

  10. Select the Access Rules tab.

  11. First, create a LAN to WAN rule.
    o Select the LAN to WAN option in the access rules matrix, as shown in the screenshot below.

Click the Add button. When you do this it will pop up a window where you can create the actual access rule. Set up the access rule using the steps below.

  1. Choose the Service drop down and select Any.
  2. Choose the Source drop down and select Any.
  3. Choose the Destination drop down and select Create New Network. There will be four fields, fill them out as follows.
    o Name - Nextiva
    o Zone Assignment - WAN
    o Type - Range
    o IP Range - 208.73.144.0 through 208.73.151.255
  4. Select the Add button. It will show a message that says “Rule action done, please check rule table” if the rule was created properly.

Then we must create a WAN to LAN rule.
• Select the Access Rules tab again, it will open the rule matrix back up. We will then select the WAN to LAN option.

• • Click the Add button. When you do this it will pop up a window where you can create the actual access rule. Set up the access rule using the steps below.

  1. Choose the Service drop down and select Any.
  2. Choose the Source drop down and select Nextiva, which you should have created in the prior LAN to WAN step..
  3. Choose the Destination drop down and select Any.
  4. Select the Add button. It will show a message that says “Rule action done, please check rule table” if the rule was created properly.
    • Once these rules have been created all firewall exceptions should be set up to allow traffic to/from Nextiva servers properly.