I guess some more information is in order.
The short answer is that it is tied to +5V on my custom board.
Long story is that the hub device is paired with a power control switch (TPS2041) for downstream devices. The PWRON and OVRCUR I/O is configured for ganged mode and so all the +5V to downstream devices is switched as a group. I don’t use the USBH_CPEN signal to do the power switching and instead use the hub and switch combination and I initially had the +5 to the USBH_VBUS attached to that +5V output . When the hub device did not work (did not assert the PWRON signal outputs) I thought maybe it needed to have that +5V in place to communicate with the hub so I white wired it so that USBH_VBUS always has +5V.
From: Keane, Ben (STRX) [via Gumstix] [mailto:[hidden email]]
Sent: Tuesday, December 18, 2012 6:49 PM
To: Crossley, J. Eric
Subject: Re: Embedded USB hub
What have you done with USBH_VBUS (Pin 32 on the J4 connector - if you copied something like the chestnut43 board) line on your custom control board? I believe this needs to be pulled high to 5V so the gumstix knows there is something connected downstream (like your hub).