Is
Dhammakaya meditation compatible with a mindfulness of breathing?
Certainly.
You can this by placing your awareness at the centre of your body.
You can feel the full extent of the breath, from the beginning
to the end. Aanaapaanasati means the awareness of in-and-out breathing.
So you can call Dhammakaya meditation, aanaapaanasati or mindfullness
of breathing. However, there is more to Dhammakaya meditation
than this. Dhammakaya meditation also employs the practise of
visualization using "kasina" (concentration on a subject
or image which we use as a nucleus for our awareness), which is
internal to our body. Above all, the most important thing about
the Dhammakaya meditation technique is that the awareness is placed
at the centre of the body. With the attention here, inside the
body, instead of outside the body (as is generally the case with
aanaapaanasati meditation), you can create not only concentration
but also self-awareness.