I noticed in Melas Performance editor that in the ARP section, it is possible to program six ARP patterns (ARP1 - ARP6) and relate them with the six buttons SF1 - SF6 for each one of the two ARPs that can play simultaneously. Is this correct?
What is the usage of this option and how is it possible to access those buttons (SF1 - SF6) in real time playback with MX?

I noticed in Melas Performance editor that in the ARP section, it is possible to program six ARP patterns (ARP1 - ARP6) and relate them with the six buttons SF1 - SF6 for each one of the two ARPs that can play simultaneously. Is this correct?

That is correct.

What is the usage of this option and how is it possible to access those buttons (SF1 - SF6) in real time playback with MX?

it is possible to dynamically change between arpeggio Types that were pre-assigned to the six SF tabs.

A System Exclusive message sent in the measure preceding the point at which you want the phrase to change can be used to dynamically recall arps. If you want the Arp phrase to change for the top of measure 009, send the message anywhere in measure 008.

F0 43 10 7F 17 36 30 00 dd F7

where “dd” is the Data Byte 00-05 for SF1-SF6. This message can be input to a MIDI track routed to the MX from your DAW to automate arp phrase during playback. For example, you might find one arpeggio phrase suitable for the Verse and a different arpeggio phrase suitable for the Chorus and yet a third for the Bridge, and so on. (Verify that your DAW is configured to send System Exclusive… Many DAW default to filtering sysex).