Just got a call from Schwab. They said that Pink Limited securities should be able to be traded online, and that there is a system issue preventing this currently, but their IT team is working on a fix. They said there is no ETA to complete the fix. I don't know that I buy that story, but the guy I spoke to said these should have never been restricted for online trading, which directly contradicts what I had been told by customer service representatives and the trading desk.