[c-nsp] ping ipv6 question

[Hank Nussbacher]

Can someone clue me in why the Cisco ipv6 ping doesn't have the option to 
provide a source IP/interface:

gp#ping ipv6
Target IPv6 address: 2001:738:0:402::2
Repeat count [5]:
Datagram size [100]:
Timeout in seconds [2]:
Extended commands? [no]: y
UDP protocol? [no]:
Verbose? [no]:
Precedence [0]:
DSCP [0]:
Include hop by hop option? [no]:
Include destination option? [no]:
Sweep range of sizes? [no]:
Type escape sequence to abort.

like it has on ipv4 ping:
Extended commands [n]: y
Source address or interface:

Thanks,
Hank