Upgrade to CRM 4 breaks Exchange web access

After upgrading a system that was running CRM v3 to v4 exchange web access stopped working. Error was "The page you are looking for cannot be found".

To get around this problem without touching the default CRM v4 website this is what I did.

Creating a new HTTP Protocol in Exchange
1. Open Exchange System Manager
2. Expand Administrative Groups -> First Administrative Group -> Servers -> <Your Server> -> Protocols -> HTTP
3. Right click HTTP -> New -> HTTP Virtual Server

You can't run multiple websites on the same port unless they have different host names.
4. Click on Advanced under the IP settings -> select the default entry -> click Modify -> specify a new host name
5. Give this virtual server a name and leave the defaults and click OK.

6. Expand Exchange Virtual Server (first one under HTTP)
7. Right click Exadmin -> Properties, make a note of the properties and their values
8. Right click the new virtual server you just created -> New -> Virtual Directory -> Fill in the properties/values you noted from step 7
9. Repeat these steps for Exchange, Microsoft-Server-ActiveSync, OMA, Public

Tweaking IIS
We need to tweak couple of things in IIS to make this work with active sync.

1. Open IIS Manager
2. Expand <Your Server> -> Web Sites -> <Newly created Exchange Virtual Server>
3. Right click Exchange -> All Tasks -> Save Configuration File -> Save it somewhere
4. Right click <Newly created Exchange Virtual Server> -> New -> Virtual Directory (from file)
5. Select the file you saved in step 3
6. Click Read File
7. Select the first entry (Exchange)
8. Click OK -> Select Create new virtual directory

As far as I know step 9 is only required with SBS
9. "exchange-oma" should be the name of the new virtual directory
10. Click OK

That's it, you'll be able to access Exchange Web using the new host name.