The management frames shall be added as a sub-packet in the IEEE_802_11Packet class.
Especially interresting info to extract is the SSID parameter name from Probe Requests ("wlan.fc.type_subtype == 0x4" in Wireshark) and Beacon Data.
See "802.11 - 1999.pdf" chapters:
* 220.127.116.11 Beacon frame format
* 18.104.22.168 Probe Request frame format
Each management frame format needs its own class.