Connecting a MSM4xx Accesspoint to a 802.1x secured switchport

[JvR_NM]

Hello,

We try to secure our AP's with 802.1x to the switchport with W2K8 NPS. Everything works fine, NPS see the AP and is granted. Problem is clients can connect to the AP, but the switchport is blocking the clients MAC-address (Only the MAC of the AP is granted). Client's have no connection to the network and won't get a DHCP address. When 802.1x is removed from the switchport everything works fine.

This is what the MSM760 says when using 802.1x to secure the AP: 

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The switch port is expected to be multi-homed, so that once authentication is successful, tagged and untagged traffic for any MAC addresses (including wireless clients) will be accepted by the switch.

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We have HP2520 and HP2610/20 (POE) switches, will this work on these switches ? (can't find anything about it) I tried it with client-limit rules on the switchport but still same problem (and is limited to 8 MAC addresses).