Here is how I have done it. You will want to use the script in this thread Image to Layout (Logic) to convert a logo to lines and then place into a PADS Logic schematic. Convert the PADS Logic schematic to xDX Designer.
Thanks for the suggestion, this way I have been able to import our Logo to a xDX schematic sheet, (however the resulution in xDX was not as good as in Logic).
But I have still not been able to add the logo to the Border symbols in Symbol Editor as graphics (not picture).
Like in the sample library (picture below).