Ryan, Thank you for the "teach a man to fish" approach. Though I didn't find the documentation to be very clear, I was able to set the property using the syntax below.
c:\Temp\800>svn propset svn:externals "ver_1.0 svn://3.x.x.x/trunk/Customer1/system_800/ver_1.0" . property 'svn:externals' set on '.' This worked for the directory listed above. I then added several external definitions, but when I finally committed and checked out, it seems that only the last definition was applied. Evidently I overwrote the previous definitions. Can I add multiple external definitions? If it's in the "svn help propset", I am not seeing it. Amad