2510G-48 w/Y.11.41 issues with client-limit for port-access configuration

[drewbles]

So i'm playing around with a switch we have lying around in the hopes of configuring up port web-based auth as per the document http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c02563879/c02563879.pdf here. 

The document states that I should be able to set a client-limit up to 32, but the CLI has different ideas:

switch(config)# aaa port-access web-based 29 client-limit
<1-2> Enter a number for the 'client-limit' command/parameter.

Now for my purposes, I need the upper limit of 32. The document above is June 2008, and Y.11.41 is from end of 2012. 

Does anyone know if the limit was reduced down on the 2510G's or is there some kind of conflicting setting that's causing this. I've put the relevant config below:

aaa authentication port-access chap-radius
radius-server host 192.168.1.10 key peter217 auth-port 1812 acct-port 1813

aaa port-access authenticator 29
aaa port-access authenticator 29 client-limit 2
aaa port-access authenticator active
aaa port-access web-based 29
aaa port-access web-based 29 redirect-url "http://www.microsoft.com"
aaa port-access web-based dhcp-addr 192.168.70.0 255.255.255.0

The setup appears to be fine (I get the login screen on the web browser and it's happily DHCP'ing out 192.168.70/24 IP's). Just curious as to why I cannot set the client-limit to 32.

Any suggestions appreciated:)