LG NPST is the modern equivalent of LG Download. It's a provisioning tool used by LG and Verizon to flash new firmware, preform NV edits, load new PRLs, etc. You'll need the lab installer as well, which opens up full access to the program.
PST from any manufacturer is Product Service Tool.
There's a 1.0.6 stable release that I've used many many times to edit and/or replace the filedb file on Voyagers and Dares. There's also a 1.0.7 test release. You should get the latest stable release and try it out, and if that doesn't.. try the latest test release. You may need to uninstall previous versions and then install the new one.