I had a Sony KDL-52WL135. Then I returned it and got a KDL-52XBR4.

Harmony's database has a piptoggle button for the 135, even though the original remote doesn't have this button. Without the Harmony, you need four clicks to turn PIP on or off. But with my Harmony I could just hit piptoggle. Totally awesome.

The Harmony database for the xbr4 does not have a piptoggle entry. But the two tvs are so similar I'm getting away with letting the harmony think my xbr4 is really a 135, and piptoggle works (even though the xbr4's remote also lacks a direct pip button).

So I don't have a problem, just a couple of questions.

Why did the support person I talked to at Logitech refuse to copy the piptoggle code from the KDL-52WL135 record to the KDL-52XBR4 record?

Is there a way to add this command to my own profile without having a remote that actually sends the piptoggle command?

Given that the KDL-52WL135 remote doesn't have a piptoggle button, how did piptoggle find its way into the KDL-52WL135 record in the first place?

Logi ought to have copied it - ask them again, by email and phone.
There are lots of these extra codes in the database; people have various ways to work them out and get Logi to include them there.

You can also use one of these solutions:
1a) If the dataset for the KDL-52WL135 has all the necessary commands, then just use it.
1b) If the dataset for the KDL-52WL135 is missing some commands, then use both.
2) If you have another learning remote, then use it to teach the command back to the Harmony.
3) There is also the unsupported IR Analysis Center "Backdoor" method to enter a Pronto command but heed all the Warnings. The "Backdoor" method is a "Use at your own risk" and is not for the faint of heart: [Link: remotecentral.com]

Yes, for 1b if you have the new TV for your watch TV activity you can just add the old one as an additional device and the command you want will be available in it for you to customise to some button.
I'd insist on Logi doing it for you though!

...and for 1b, don't forget to set the power settings of the "dummy" TV device to "no power button".