How can i add into TAB - "attachments" for CI form columns, for example, create date of attachments (sysmodtime)?
In that case, you can't; not really.
In later versions, HPE improved the Attachments form element to include date and size, who attached it and when. But in the earlier versions, it just lists the attachment name. You could try and fake it with a virtual join to the SYSATTACHMENTS table and display whatever data is there, but you can't modify the Attachments form element itself.
Looks like i found familiar solution, but can't understand how does it work.
There is a HTML-Viewer element on a form (ess.browse.request) with some value in input field - $mos.html.attach
Where can I find how the html-form is formed ?