According to Kant, while thinking of empty concepts without intuitions, what do we synthesise?

(This will be my last question on this book, for those of you getting bored of my questions).

Very briefly I will describe the method of Transcendental Deduction (TD) in an over-simplistic manner, and I want to know how do the indeterminate thoughts of metaphysics (God, Soul etc) are formed given TD is correct.

So there’s a transcendental unity of apperception which presupposes a synthetic unity of apperception ("I Think and all that given in para 16-17 in TD"). This synthetic unity requires intuition (understanding has to synthesize something – in this case a manifold of intuition), and since this unity is the condition for my self-identity, understanding should always accompany intuitions, otherwise they are empty and analytical. [Correct me if I am wrong here, this is an oversimplification of course].

Now, my question is, how are metaphysical statements even formed?

P1: Intuition is required for thinking (para 16-17 in TD as described above).
P2: We think metaphysical statements. 
C1: There must be intuition in these metaphysical statements.

But the whole reason why Transcendental Dialectics was written is because metaphysical statements do not have intuition.

What’s the missing piece of the puzzle? For me, if you disagree with P1, there goes the tedious explanation of Deduction, because I attribute these metaphysical thoughts to myself, and therefore synthesis DOES occur. Can there be synthesis of something other than intuition too, perhaps what Kant calls ‘psuedo-objects’? If that’s true, are these ‘psuedo-objects’ not intuited?