You can create HTML Composer spots like common spots in IXM One.
To do so, perform the following steps:
In IXM One, go to Content > Playlist.
In the Spot groups pane, select the spot group to which you want to add the new spot.
Click on New and select New HTML Composer spot.
In the Create a new spot window, enter a Name for your spot.
Specify all other spot properties as required.
Click Save to save your spot.
Once you've saved the spot, the HTML Composer opens and you can design your spot.