Hi Dale,
Nearly everyone that first starts using an Icom radio with a hot-spot makes that error. Never use simplex, always use duplex (+ or -, it doesn't matter) with zero offset. When you set an Icom radio to simplex, it transmits "DIRECT? " in the RPT1 and RPT2 parameters of the header, no matter what might be indicated elsewhere on you radio, and when that happens, your hot-spot won't send your voice stream anywhere.
I vaguely remember discussion in other forums that the 70cm DVAP is a bit more temperamental than the 2M DVAP, but I don't know if that is the source of you problem. If echo is working, then there is probably nothing wrong with the DVAP and I don't have a lot of good advice for you. If you are linking, make sure you are showing up as linked on your target's dashboard. For example, link to XRF735A. That's a much less crowded reflector channel that is also connected to the Quadnet Array, the you can look on to see if your hot-spot module is shown on the right side of the "Last Heard" page. Then when you transmit, the Last Heard page should show a new row for you at the top of the list. If that's working, just keep putting out a "Radio check" call. Somebody will eventually respond.
Tom Early