Case sensitivity challenge

Stream profile will only work against response data, so that won't do the inbound URI re-writing you need. (But hold that thought, you might need to use it to re-write links in the response -- more on that later.)

First, I'd assume that the URI's received by LTM have substituted %20 for the space character.

From there, you could use the following iRule to re-write inbound URI's to the correct case with the internal path:

class URImap {
  "about%20us About%20Us"
  "corpcomm CorpComm"
  "leading%20the%20path Leading%20the%20Path"
}

rule iRule_URI_mapping {
  when HTTP_REQUEST {
    set OldRootDir [string tolower [getfield [HTTP::uri] "/" 2]]
    set NewRootDir [findclass $OldDir1 $::URImap " "]
    if {$NewRootDir != ""}{
       prepend portal path to requested URI & re-write URI with proper case
      HTTP::uri /irj/portal[string map -nocase [list $OldRootDir $NewRootDir] [HTTP::uri]]
    }
  }
}

Here's a post on a similar topic, a few more complexities but overall similar to yours:

http://devcentral.f5.com/Default.aspx?tabid=53&view=topic&forumid=5&postid=13912 (Click here)

Note the details re: stream profile for payload link translation to remove the internal path references (required if your server returns absolute rather than relative links in the response):

-- Source: /irj/portal

-- Target:

and also more logic to re-write redirects containing the internal path to the external presentation.

HTH

/deb