after doing that, add the following to your file:
title sol10_u8_0910_x86
bootfs rootpool/ROOT/sol10_u8_0910_x86
findroot (pool_rootpool,0,a)
kernel$...
try a "ifconfig aggr1 down" and after that, try again with the ping. you have two interfaces in the same net/subnet. so the ping might go out through the other interface.