How to increase ptys in ESXi host.

Hi All,

     With ESXi 4.1, I found that I can only open 8 ssh connections at the same time, when I try to open the 9th, there will be error "connection refused,can not allocate ptys", and I found there are 8 ptys (pty0~pty7)in my ESXi host.

I want to know how to increase the pty numbers or if  possible is there another way to support multi-user accessing like "telent,rlogin" from remote ?

thanks.