I'm now using Sling SOLO in Taiwan.
What I can find is only PX VC-181 CATV converter box.(http://www.px.com.tw/e/p04-pro_1_1_1.php?Kt_no=G&Ks_no=G007&Kp_no=VC181)
However, this device is not in the list and my slingbox can't work.
The main issue is that your set-top box is not included on the supported devices list. However, we recommend you to check the following thread, provided by alanrichey42.