A few things to check:

[*]Make sure the surround back speaker is turned on in the 1050's menu (which you indicate you have done)
[*]Put a disc in that has a Dolby Digital 5.1 soundtrack. Surround 6.1 will not work without either a Dolby Digital 5.1 input or a 5.1 analog input, and since you don't have the six-channel analog connections made we'll leave that option alone for now.
[*]Turn on the "Surround 6.1" mode using either the remote (very bottom left-hand button) or the button on the face of the 1050. At this point, the surround back speaker indicator on the 1050's display will light up and the "Surround 6.1" indicator will also light up.

Let us know if that gets you on track or not. (Oh, and thanks for the faith in me, michael )

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