Sorry, thought I had responded to this already. My original posting had a BIG typo in it. My 1st sentance should have read:
orry, on the 2x4SFP Uplink Module, you can NOT mix and match 10GE and 1GE."
You cannot use the hardware for both 10-gigabit mode and 1-gigabit mode simultaneously; only one at a time.
As I stated, this piece of documentation is inaccurate in regards to the operation of the EX4300, although Juniper may decide to not support such a combination. This is being looked into.
The config commands mentioned to NOT apply to operation of this module in an EX4300, only for an EX4200 due to hardware differences between the 2 platforms. Basically set chassis pic mode is not a command that is associated with EX4300, only EX4200.
I can update this thread once I know more about EX4300 operation/support.