Does my sound card support 5.1 surround sound with speakers?

I own the asus xonar dg sound card http://www.newegg.com/Product/Product.aspx?Item=N82E16829132020&Tpk=xonar%20dg i know it has dolby headphone technology to simulate 5.1 surround sound, however i want to know if it can perform DOlby Digital 5.1 surround sound (a lot of tv broadcasting uses this, and if it capable of DTS surround sound. I have it connected to my logitech z906 5.1 speakers through an optical cord and the sound does seem to be coming out all the speakers i just can not tell if it is some type of virtual surround feature or if it is running true dolby digital 5.1 and/ or dts 5.1 surround. i called asus and they said that the card only has dolby headophone technology, however the box says under sample rate and resolution "Dolby Digital, DTS" this wear I am confused. Can anyone verify this?

Not sure exactly how it works, but the hub for those speakers can decode DD 5.1 and DTS sent over optical (the speakers/amp need this to get surround sound from optical signal). This vid is good for testing surround sound.C_Rule

[QUOTE="C_Rule"]Not sure exactly how it works, but the hub for those speakers can decode DD 5.1 and DTS sent over optical (the speakers/amp need this to get surround sound from optical signal). This vid is good for testing surround sound.merigoldsass