Ah, well, I should have thought of the Wiki... I've been unable to determine exactly how to set up the necessary conversion because I don't have a handheld to plug in and configure. It appears, however, that if you go to Tools->Options->Handheld, just plugging it in and configuring it should answer that part of the problem; the wiki makes it pretty clear that file conversion is one of the options you can configure.
I can help with the checkbox though, as I used the checkbox in iTunes myself before I moved my library to JRiver. If you go to Tools->Options->Library & Folders, there is an option called Manage Library Fields. If you click that, it will show you a list of all the fields in the database. From there, you can click the "Add New Field" button beneath the list with a name like Sync or whatever. (
Note: There
may already be an appropriate field for you to use, but I've customized my database so much that I have difficulty telling what the stock fields are anymore.)
To create a CheckBox field, select the Data Type as "Integer", set the Edit Type to "Check", and make the Acceptable values read "0;1". Now you have custom checkbox. Yay! What do you do with it?
Well, in any view where you have the List Style set to "Details", you can right-click on the column headers and add you field to the displayed columns. From there, you can check or uncheck to your hearts content. Alternately, any time you have a file selected you can open the Tagging pane (click Tag from the Action Window beneath the treeview), find the field, and check or uncheck there.
Finally, you'll need to create a playlist that you can select in the Handheld section of the Options screen. If you go to Playlists in the treeview and right-click it, you can choose Create Smartlist (alternately, you can hit F9). This will be pretty straightforward if you're familiar with iTunes's smart playlists, but the idea is to create one called "Stuff To Sync" or whatever and setting a Rule that says "Sync" "is" "1".
I hope that helps... and I hope the wiki helps in setting up the both the device and the conversion configuration. If not, someone smarter than me will doubtless be able to explain it. For that matter, someone smarter may follow this up with a much easier solution to this. Sorry, I'm just trying to get started answering questions around here, so I'm never quite certain I'm doing this right... or should be doing it at all
