When it comes to your email - you have a choice...
There is a great article and download on Lync Mobility from Microsoft here.
One thing that it doesn't specifically cover _exactly_ is the Lync App from the Windows Store for Windows 8.
When using iOS, Android or Windows Phone devices we can specifically set an https url location for the lyncdiscover service, for example: https://lyncdiscover.contoso.com. However this is not possible to set using the Windows 8 app.
So Lync deployments that have multiple SIP domains in use but only one lyncdiscover record on these devices manually enter https://lyncdiscover.contoso.com, if they have a SIP address of email@example.com, but are ultimately part of the same Lync infrastructure.
In the above guide it mentions using CNAME records to create for example, a lyncdiscover CNAME record for the tailspintoys.com domain, pointing it to lyncdiscover.contoso.com.
Now if your reverse proxy solution only has port 443 open this redirect will fail on Windows Phone and iOS devices. Newer Android devices appear to be able to cope with the redirection and bind to SSL ok, hence many organizations simply entering the lyncdiscover record manually in the setup information.
But as I said this work-around doesn't exist for the Windows 8 app. So here's what you do.
1. On your reverse proxy solution as well as having the 443-4443 redirection to the Lync Director or Front End pool that owns the this lyncdiscover endpoint, also add an 80-8080 rule. This will then allow a CNAME in DNS to work on iOS and Windows Phones, and also the Windows 8 app.
2. Once this is configured simply open the Windows 8 Lync app and when logging in you will receive a redirection notice (which just like autodiscover redirects for Exchange you can set to only prompt the first time)
2. You will, if familiar with IM integration in Exchange 2010, be immediately at home here. However for IM integration in Exchange 2013 we only set two of the above four values. The values are ‘InstantMessagingEnabled’ and ‘InstantMessagingType’. We leave both ‘InstantMessagingCertificateThumbprint’ and ‘InstantMessagingServerName’ blank. This is very important as it actually does break the integration between Lync 2010 and Exchange 2013.