You are correct. The solder you use as a plumber is low temp. You can use the gas/air torch you use for high temp "brazing". I brazing is the more acurate term for what we do in joining metals together. Silver soldering/brazing uses silver alloys that melt at a lower temperature than the base metal we are joining. The flux is different and I would recommend staying away from fluxes containing fluorides. Silver solder without cadmium is best for safety. "Silversmithing" is an excellent book to learn from. Low temp solders (lead/tin based) will contaminate the silver and ruin it.
Always wear protective clothing. I use protective sleeves and respirators when dealing with metals and such. Also a good pair of gloves is always a must. Try www.asasupplies.com for some of these safety supplies.