It seems the multi vlan command feature is only supported on the 2900 and 3500 series switches, personally I have never had the need to used this command but from what I just read although switchport multi vlan is not the same as if you were using dot1q trunk but it resembles same effect , so you may try trunking the port and test it as long the PC NIC supports dot1q you should be good.
the port commands for dot1q encap is:
switchport mode trunk
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 2,3,4,5 etc..
Regards
Jorge Rodriguez