I don't think that solution would work to adapt the VGA signal to the HDMI monitor. From that Amazon link above:
"
Important Note: it cannot transmit signals from vga to hdmi because it is NOT a bi-directional adapter cable."
While it's not what was requested, another possible option is to find a 'modern' monitor that can accept either the Amiga native 15kHz RGB video or the VGA video from the Picasso II. This is a useful reference for finding such monitors:
http://15khz.wikidot.com/
