I’ve struggled for a long while to find something suitable too.
I know you say Z-wave, but I’m transitioning some lighting and sensors to Zigbee, specifically Philips Hue. The ALTHUE bridge by @amg0 works a treat on Vera with Hue indoor motion sensors.
I haven’t got an outdoor sensor yet, but take a look here:
https://www2.meethue.com/en-gb/p/hue-outdoor-sensor/8718699625474
AK