as long as they share the same neutral wire you can take
hot off the 120 plug run it to the one of the hot sides of your 220 in
1 hot off the 220 plug on the gen (2 of the 4 prongs will be 120 hot) to the other side of the 220 in
combine the neutrals and ground and you should have a total 27 amps 220
not to sure on this, id ask an eletrican or hopefully someone else will chime in
hot off the 120 plug run it to the one of the hot sides of your 220 in
1 hot off the 220 plug on the gen (2 of the 4 prongs will be 120 hot) to the other side of the 220 in
combine the neutrals and ground and you should have a total 27 amps 220
not to sure on this, id ask an eletrican or hopefully someone else will chime in