AAL5 and winsock

Hi,

This post is not directly related to driver programming but rather I need
your inputs to get some of the funtionalities provided by driver in user
mode code.
We have an ATM based application where we need to set User To User
Indication byte in AAL5 frame before sending it. Currently, we are using a
TDI driver to achieve same (using NDIS_SET_PACKET_MEDIA_SPECIFIC_INFO macro)
and it is working fine. Now we are thinking of using winsock send AAL5
frames and remove driver completely. However, we are not able to set
UserToUserIndication byte in the CPCS trailer for AAL5 frames using winsock
approach. I couldn;t find any information on setting this information and
looks like no documented way to achieve same.
I will appreciate your inputs on how to achieve this using winsock.
Regards,
Yusuf