You will be able to use the Line in inputs on the sub. Just connect the 'Subwoofer' output from your receiver via a digital coax wire to any one of the inputs in Line In. Or get a Y-adapter and use both Line in inputs.
The receivers you are looking into don't have an L+R sub output. They have 2 LFE outputs, meaning you can hook up 2 subs. A Y splitter will do or following your sub manual direction for hooking up the LFE cable (I think it is the left input in your sub.) I think the subs have L+R to be use on different kinds of preamps and not in AV Receivers, but I'm not really sure.