Using the AF540FGZ with 35mm

Anyone out there who can help clear my confusion? I've just bought an AF540FGZ to use with my K20D, but, being eccentric and attached to traditional methods, I would like to use it on an LX as well. According to p27 of the manual, I should be able to set the flash mode to TTL, but I can't. The modes I can select are P-TTL, A, M, and SB. What have I missed/misunderstood? The Pentax Service people are helpful, but the first step seems to be to send the flash in to check for a fault. I think misunderstanding is more likely than malfunction, so please let me in on the secret if you know how to do it.
Thanks.

Read the last paragraph on Page 60 of the manual (Referred to on Page 25, referred from Page 27 - Confusing - of course).

When attached to an LX, Super A/Super Program, or 645, the flash display shows P-TTL, but the image is taken using TTL.

That's interesting - the AF360 would show either P-TTL or TTL, depending on which body it is attached to.
Thanks for that Peter
Matt

Wow! That's quick service. Thank you Peter. I knew it had to be something like that (and I'm not a great reader of manuals).
Regards,
John C