Daikin Atherma LT buffer and solar.

Hello I'm new to this forum
I have Daikin althemra LT split type witch im already using for two years and i need some advice about a thought i have stuck in my head for some time.
The pump is used only for space heating, heating with rads, there is no DHW, as on the picture.
Attachment 15089
Since i have a lot of sunny days during the winter and those days the ambient temp can come up to 15C, I'm thinking of adding a buffer tank with some solar vacuum tubes witch will support the heating, all of the parts will be non daikin as on the pic.
Attachment 15091
Here is the problem.
How to make the both systems work at the same time?
As the manual says, the altherma will shut off if the heated water is more than 55C.

On a sunny days, the pump dosen't cycle very offten, and the produced heat from solars could pass the 55C boundary. The circulating pump from the altherma wont turn on to cycle the water and slowly dump the heat in the rads if the heating demands are satisfied.

If i make the buffer as auxiliary heating, than the buffer will be non usable from the altherma and will be only used for heating from the solars.

Is this possible to work somehow or it's not worth the trouble.
So any advice is welcomed.
Sorry for my language, as english is not my native language.

Daikin sell an auxillary pcb that allow an interface with the solar system. It is normally used with DHW cylinder but I don't see why it couldn't be used with a buffer

I did some research and I could not find any solution where the the hot water from the Altherma is directly reheated from a closed loop systems.
But i did found the pcb for the auxiliary connection (EKRP1HB) and now I have some problems understating the wiring.
In the manual for my indoor (EHBX) unit there is an example of wiring to auxiliary heating https://prnt.sc/im5cg6 which doesn't tells me much. I'm confused about what kind of contacts/inputs and from where are connected on X1/X2 and is the alarm output needed.

In the mean time I found a manual from a EKHB* unit which does makes more sense to me http://prntscr.com/im5krp where you have an auxiliary contact via relay for activating the second heating source. This again is a piping from the same EKHB* manual http://prntscr.com/im5lmt which is closest to what I'm planning to do.

Will the wiring scheme from the EKHB unit going to work for EHBX unit too. What happens when the auxiliary heating takes control, does the altherma completly shuts off or is in some stand by mode waiting for the reverse signal?

By connecting a volt free relay on your auxillary heat source (solar, boiler etc ) across the EKRP1HP you will stop the Altherma when the relay closes.
In conjunction with this you will need a pump on your auxillary heating circuit to enable the buffer to take the auxillary heat.

When connected to a solar controller, whenever the solar has greater temperature than the cylinder/buffer, it energises it's pump and then signals the Altherma to stop. Once the solar temperature falls below the cylinder/buffer temp, it stops it's pump and releases the Altherma to operate.