Thank you for your question. A small diameter brad nail (up to 3d, or 0.0803” diameter) should be able to go through the vinyl with no problem, but be aware that you need to have something substantial behind the bead to hold the wooden trim: don’t rely on the vinyl to resist pullout of the brads by itself. Also realize that putting brads into the vinyl trim may not break the trim itself, but will likely crack any finishes such as drywall mud that has been applied and feathered at the edge of the bead. If you need a longer nail such as 4d or 5d with approximately 0.10” diameter, check in an inconspicuous area to see how the bead performs. A nail like this can go through the bead without cracking it, but it depends upon several factors including where in the bead it is installed and how close it is to an edge or another nail. Try to keep edge distance of nails in the bead at least ½” and spacing at least 3”.
Although intended for indoor use over drywall, the vinyl bullnose corner bead, like most vinyl products, could conceivably be used outside. It has not been tested for long-term exposure to sunlight and repeated freeze-thaw cycles, so it could become brittle over time. Also, make sure that any fasteners used are rust-resistant to avoid staining or streaking the bead.
If the corner is a true 45 degree angle, there may not be an appropriate bead that works in the bullnose style: consider one of the flexible metal/paper faced products. If you want a wider than 90 degree angle (90 plus 45) then There is a similar product called gripSTIK 3/4" Bullnose Splay that works well for the wider angle corners. The splayed flanges can easily accommodate the larger angle.
this is for outside corners only, and is not suitable for inside corners.
Hang drywall as usual. Mud it in and let it dry. clean off the bullnose and then wipe it down with a wet cloth. That is what I did and it turned out great. Easy to paint as well. Don't over think it.