Output BFSK signal as double 1x1 instead of vector [Samples per frame]

Hello, I have a following model:

I'm modulating BFSK signal, then transmitting it thru AWGN channel, demodulate and compare the result.

If I don't use buffers everything works fine, the BER equals to 0. However, in such case the signal is a vector with a size [Samples per frame].

I want to transmit the signal thru phased array RX block, but it requires the signal to be a 1x1 double. To do so, I've tried to use Buffer and Unbuffer blocks. For some reason this did not work, I'm getting BER of 0.4 instead of 0.

Please help