Not sure about Powericons, never used it.
But I guess you'd save the icon set by selecting them all and going to "snapshopt icons" from the pull down menu.
Then to save the RAM disk icon, you'll have to copy RAM:disk.info into into ENVARC:Sys/def_ramdisk.info
If you run Powericons from Startup-Sequence or User-Startup then use Ryu's idea.
Or if it's in WBstartup, then add an icon tooltype like: STARTPRI=-100
And as Ryu said, don't forget to RTFM :-P