Your screenshot confirms, that all pre-defined properties for AutoCAD work. The reason is, that these are already mapped.
To enable a new UDP to be used in AutoCAD follow these steps:
Create the UDP, e.g. "MyProperty" and map it to a custom file property. Add the property to your AutoCAD file category. For now the property will not display on the drawing, but in the VDS dialog's dynamic grid. To display in the drawing, the drawing property need a AutoCAD MText or Attribute link.

To directly use block attributes you need to have 3 configuration settings:
1) ADMS Server: Index block attributes for block name, e.g. ISO_TITLEA (This setting is not related to VDS). 
2) AutoCAD.cfg: the block name has to get registered, e.g. ISO_TITLEA like this:
....
<TitleBlock>ISO_TITLEA,ISO_TITLEB,DIN_TITLE</TitleBlock>
</Configuration>
3) Your UDP "MyProperty" needs to get a mapping to the file attribute (=block attribute name) and block attribute, e.g. ISO_TITLEA.GEN-TITLE-DES2
The secondary mapping is highly recommended to support existing legacy data, that don't have the file property usually.
The 4th setting is optional to get the label changed from GEN-TITLE-DES2 to "MyProperty": add this UIString translation:
<!--AutoCAD title block attributes / file properties for dynamic properties-->
<!--use to change display name for localization or user friendly naming-->
<UIString ID="GEN-TITLE-DES2">MyProperty</UIString>
Markus Koechl
Solutions Engineer PDM, Autodesk Central Europe