It will upshift, no way to hold. Maybe some tuner will mod this, but not yet.
GL with your search havoc, and don't let the lack of gear holding be what stops you, it is a great car.
Car:2008 E90 335i | BSM | ZPP | ZSP | 6AT Paddles | Black Leather | Dark Burl Walnut | Heated Seats
Mods: (All OEM) | BMW Performance CF Splitters | BMW Blackline Taillights | BMW Rear Deck Spoiler | BMW Performance Auto Shift Knob and Alcantara Boot | BMW Black Dakota Leather Split Folding Armrest | BMW Euro Fog Light Switch | BMW Style 193M Wheels | BMW Performance Gloss Black Kidney Grills | BMW Front Clear Bra | BMW Performance Steering Wheel (non-elec)