Unlike Cisco switches, HP switches do not allow all VLAN's by default on their trunk ports, you have to explicitly allow them.
To communicate between HP and Cisco, you will have to use Dot1q like you are already doing.
I don't know the exact command structure on the HP switches to allow VLAN's on a trunk, but if you post the output of the show run, it will jar my memory.
Also note, that the HP switches only run OSPF and RIP for routing protocols, so if you want them to do any routing, you will either have to run OSPF or RIP on your cisco 6509 (as opposed to EIGRP) or run EIGRP and OSPF on your Cisco switch, and redistribute the routes into EIGRP.
And of course, the default spanning-tree protocol on Cisco switches is PVST+, on the HP the default protocol is RSPT.
Post the show run and I might be able to help you get the VLAN allowed on the trunk. I believe it is something to the effect of:
"tagged j10"
under the vlan configuration, that would send dot1q tagged framed out the J10 interface.
Being a Cisco guy, my advice is to always replace with Cisco :)
HTH,
Craig
