In the case of a D-VHS deck, it is not a good idea to string the box, the D-VHS and the TV in series.
You need a firewire connection with handshake to record to D-VHS. Use the deck that gives you this handshake. You need to get the indication from the D-VHS deck, not the set-top box.
On your JVC you need to toggle through the channel selector buttons on the front of the deck until you get an "I" (eye) on the display on the front of the deck. With the deck connected to the STB, it should assign a number to the STB. This could be I-2, or I-3 or such. When you get a number along with the "I" (eye) the connection has been made. This may take a second or two. You may have to unplug the STB from the AC and reconnect it if you don't at first get an assigned number.
Connect the playback of your D-VHS deck to the Mits TV with component cables. If you are getting a signal at the deck, it will display through to the TV through the component (not composite) cables. You should then be able to hit "record" on the D-VHS remote control and it should make a recording. If you are not using D-VHS cassettes, make sure that you are using a cassette that is good enough for a D-VHS recording, otherwise it just won't record. Some people have good success with premium S-VHS cassettes, punching the extra hole in the cassette shell.
On the JVC D-VHS output options, you can set the recorder for 1080i output through the component outputs. (This is a on screen menu selection)