This will change the PnP values of the ESS chip. The biggest obstalce is the ultrinit will allow values of like 210-250 for SET BLASTER baseport but only 220 will initialize. And since you can't use the original ultrinit to just set the baseport for the GF1 chip on the Vipermax you'll never be able to set the GF1 at 220 which megaem will complain about. You could possibly get away with 240 baseport on Ultrasnd and Megaem OK, but no guarantees and megaem will complain with a warning every time.
For it to possibly work you'd have to do this (untested!)
1) SET BLASTER=A220 I7 D3 T4
SET ULTRASND=240,1,1,11,5
2) Run ultrinit.exe
3) Run ESSCFG.exe make sure these settings for SET BLASTER are all setup through the ESS utility
4) SET BLASTER=A240 I5 D1 T4
5) Run MegaEm
Not sure if this will even work though. The ESS chip with the SB card has good quality so I fail to really see the point of using MegaEm or SBOS. MegaEm might be cool for the few games that only support the Roland SC/GM/MT-32 family of cards for music, and in that case you can totally use MegaEm without SB for this purpose (I tested that personally).
And honestly, I use my card mainly for playing demos, mods and shareware FPS titles and anything apogee, epic, id, etc. was doing at the time which all of their games supported the Ultrasnd in some fashion.