You're using data out of the "Data for Reference" folder. This is the data that is referenced when you use the <Object> tag. Base new systems on the files in the "Included Systems" folder instead.
And at the moment you can't use RA & Dec in system files, but this will be corrected in a future update.
Here's a good example of how to work with galaxies.
Open up the system "Galaxy Collision - Parallel.xml":
<System>
<Body>
<Object>Andromeda</Object>
<Name>Galaxy</Name>
<Mass>1 mw</Mass>
<Diameter>1 mw</Diameter>
<Appearance>Color-Red</Appearance>
<PositionX>100000 ly</PositionX>
<PositionY>0</PositionY>
<PositionZ>0</PositionZ>
<VelocityX>-150</VelocityX>
<VelocityY>-25</VelocityY>
<VelocityZ>-50</VelocityZ>
<Action>rotate=0,20,0</Action>
<Settings>camera=dist:120000 light year,h:2,v:-18; labels=off</Settings>
</Body>
<Body>
<Object>Milky Way</Object>
<Appearance>Color-Blue</Appearance>
<PositionX>0</PositionX>
<PositionY>0</PositionY>
<PositionZ>0</PositionZ>
<VelocityX>150</VelocityX>
<VelocityY>60</VelocityY>
<VelocityZ>50</VelocityZ>
<Settings>timestep=30000 y;focus=center</Settings>
<Action>rotate=10,0,0;</Action>
</Body>
<Body>
<Object>Sun</Object>
<Name>Star</Name>
<Mass>0</Mass>
<PositionX>0</PositionX>
<PositionY>26000 ly</PositionY>
<PositionZ>0</PositionZ>
<VelocityX>0</VelocityX>
<VelocityY>0</VelocityY>
<VelocityZ>0</VelocityZ>
<Action>orbit=Milky Way</Action>
</Body>
</System>
It's often best to use the <Object> tag then just add the additional properties that you want to change and override, like <Name> or <Mass> or <PositionX>
1 mw = Mass of Milky Way
1 ly = Distance light travels in 1 year