No you are not screwed really, you just won't have an all s-video arrangement. More than likely your receiver just doesn't convert composite signals to s-video, but can use both types of connections, your manual just doesn't cover this. Make the exact same connections you made before to the same inputs and outputs, but now use a composite connection. IMPORATANT ! Keep the s-video connection as it is, you will be using both.
RCVR composite Monitor out > TV composite input as used before
DVD/VHS Rec. common out > RCVR composite input as used before
When you play a DVD, it is possible that both the composite and s-video connection will be output simultaneously, if their is a switch to turn off composite output for the DVD player side, use it. If not, you'll need to test that the receiver and tv are defaulting to the s-video connection.
To do this simply start up a dvd with all the connections made and pull the composite video connection from the dvd player while in operation. If you lose video signal then you know you are going to have to unplug the composite cables everytime you want to watch a dvd using s-video. If not, you know you are good to go.
Keep in mind all VHS operation requires the composite connection.
Why they don't make all of these units S-VHS capable I'll never know, it's not like the technology doesn't exist. I guess it would raise the cost.