Need a repertoire against Reti

I need help finding a repertoire against the Reti (1 Nf3) as Black. Here's what I usually play against other openings as Black:

vs. 1 e4: Caro-Kann (primary), Sicilian Najdorf (secondary, played on occasion)

vs. 1 d4: Semi-Slav (primary), Nimzo-Indian (secondary, played on occasion)

None of those openings appear to work against the Reti, though I have tried a Slav-like system with limited success.

Please help.  Thanks.

How about 1...Nf6 2...e6 3...b6 4...Bb7 and 5...c5?  Of course you'll need to make adjustments according to the position:

If that's not to your taste then the New York System is a viable alternative:

Hi gundamv--the Reti is such a diverse system that there's really nothing in particular that fails or succeeds spectacularly against it.  White holds back his center pawns with the flexibility of c4, d3, d4, e3, g3, b3, or 91489570350231 other arrangements.  So you just want to make sure to avoid overextending yourself with too many pawn advances too soon.  As a Caro and Semi-Slav player, the c6-d5-e6 triangle might make sense.  Nf6 is natural, along with Be7/Bd6, and your c8 bishop either goes to f5/g4 early or hopes for freedom somewhere down the road.  Your other options are an early ...dxc4, leading to more of a Catalan/QGA, or ...d4, when you support it with ...c5/...e5 in a kind of reverse Benoni formation.  You can also answer 1...c5 immediately, when c4 brings you to a symmetrical English and e4 gets you back to Sicilian territory.  Or you can anti-Reti your foe with 1...Nf6, forcing him to declare his intentions before you do.  If white plays d4 in these lines, you're back to your Indian and Queen's Gambit explorations.  So maybe think about what goes wrong with your current defense, or post a game since a picture speaks a thousand words, because really any of the above should be viable in the hands of the right person.

Yeah overextending is usually a bad policy although as white this line used to give me trouble:

As someone who plays the Reti over the board I think that c6, d5, Bg4 is most testing.  Usually it goes something like this...

I wouldnt bother, he died quite awhile ago.

gundamv, Since you play the Najdorf, play 1...c5.  Then 2 c4 Nc6 3 Nc3 Nd4 is provocative!

Try g5 as a surprise move.I tried it once in a tournament to try and confuse my opponent but i ended up well beaten as i became totally confused.