The DSG equipped cars ECU will accept a manual trans but it doesn't work the other way around. I looked I to this and collected a lot of information on it. If going manual to DSG it's a huge pita, new harness, ECU, D/side axle, etc.
But going from DSG to manual is actually a lot easier than you would think. Clutch pedal, master cylinder, slave cylinder, linkage, shifter, D/side axle, and recode ECU. That's pretty much it!
Having said that, it would still be cheaper to buy a new mechatronics unit or rebuild your DSG. If you truly want a manual, as stated above, trade your car in for one and swap parts. I ended up deciding to stick with my DSG, it's just too good of a trans.