We recently got SG300-10 and are trying to get dynamic vlan assignment working via 802.1x and freeradius. We got it so that the client plugged into the SG300 would correctly auth, IE I can see this in "show dot1x users": ...
SR632635777 ping me if you have any questions. the support person was literally the worst support engineer we have ever interacted with, so maybe there is hope that someone else could help push cisco to address this issue.
Forgot to follow up here. This is a known deficiency of how the SG300 line implements 802.1x vs how all other cisco switches implement it (and how other vendors implement it). The support tech said Cisco was unwilling to fix this deficiency (he would...