there are alot of moving pieces here.
when you say RPC are you referring to RPC over HTTPS or something different (outlookanywhere)?
here's what I'm guessing it should look like...(the long road I've been going down).
For whatever reason, Microsoft really went out of their way to make 2010 complicated. You've got something like 9 different virtual directories, one for each service, outlook address book is broken out into a different virtual directory as is the exchange control panel (options within OWA)...why? I don't know.
With 2010 you have internal and external URL's for all of these different virtual directories. When you're using a load balancer, I think the internal URL's are worthless...you're going to send all of your clients through the LTM's so that the solution can be load balanced, fault tolerant and highly available...right?
So the default internal urls are going to be https://myserver.mydomain.com/owa
or /rpc or /outlookanywhere
You need to leave all of the internal URL's alone and create external URL's for each of the services that you want load balanced. So, owa.mydomain.com, activesync.mydomain.com, outlookanywhere.mydomain.com, exchange.mydomain.com etc.
Each one of these external URL's are going to get published to autodiscover.
Each of these external URL's will become virtual servers on the LTM(s) with their own hostnames/IP addresses.
Add each of these to DNS as well as autodiscover.mydomain.com to DNS (you're going to need a virtual server for that as well)
All depending on whether you're doing SSL offloading or not will determine what kind of connection happens between the LTM and the server. From the client to the LTM you're going to want a cert, I think it's called a Unified Messaging Certificate where you can have multiple subject alternative names for the servers, services etc.
Now, onto your specific issue, I don't know whether you're trying to do outlook anywhere or if you're trying to do a regular exchange RPC connection...either way I want to say that outlook is going to try to do an autodiscover to find the settings. It goes through a series of checks to try to pull an XML file to determine where the services are located depending on where you are. If you're an external user or an internal user or if you are connecting from an Iphone or a PC or whatever...if you're trying to access activesync or outlookanywhere, autodiscover.xml gives your device the information it needs to locate the server in question to make everything work happily.
So, make sure your internal/external urls are set, make sure that everything is in DNS, you did the cas array...good.
There's an online tester that checks a few things: https://www.testexchangeconnectivity.com/
I've logged about 30 hours using this thing.
Now if you're able to hit the individual server but you can't access it through the LTM, make sure that the pool is up.
I hope this is helpful to some degree...this is not a fun project by any means, it's a serious pain in the butt and the deployment guide is not a great help (IMO).