AutoCAD Inventor :: Add Bolt From Content Center To Bolted Connections

In my work i normally use our standard full threaded rods with square nuts. But, since we make the rods and nuts in the factory, they do not follow any international standard.

I wanted to add the threaded rods to the Bolted Connection menu in order to be able to automaticaly add the rod and to let inventor calculate the needed lenght.

I was able to add the rod to content center as an Ipart with all available sizes, but it doesn't appear on the bolted connections menu.

See attached our normal bolted connection, how can I add this to bolted connection so inventor will size it automatically to the needed lenght?