Bicycle Mechanics - New shifters, can't get front derailleur to work properly

I'm trying to replace the crappy Shimano Revoshift (3x7 speed) shifters on my brother's bike with Shimano Alivio 7 speed shifters. The rear shifts like a charm, but I can't get the front to work. The chain is on the small ring and the shifter is in "1". Now, when I try to shift it to "2", the derailleur goes to the largest chainring, skipping the middle one. Obviously, shifting to "3" doesn't work.

I assumed that it would work since this is all 3x7 speed Shimano gear. Could it be that the Alivio shifter isn't compatible with the front derailleur (which I think is one of the cheapest Shimano MTB derailleurs, it only says "SIS")? Or can I somehow adjust the shifter/derailleur to shift properly?

I'm trying to replace the crappy Shimano Revoshift (3x7 speed) shifters on my brother's bike with Shimano Alivio 7 speed shifters. The rear shifts like a charm, but I can't get the front to work. The chain is on the small ring and the shifter is in "1". Now, when I try to shift it to "2", the derailleur goes to the largest chainring, skipping the middle one. Obviously, shifting to "3" doesn't work.

I assumed that it would work since this is all 3x7 speed Shimano gear. Could it be that the Alivio shifter isn't compatible with the front derailleur (which I think is one of the cheapest Shimano MTB derailleurs, it only says "SIS")? Or can I somehow adjust the shifter/derailleur to shift properly?I don't find any incomaptibility refrence. SIS is the typical shimano desigantion for components that use the same indexing system. Go through the derialier adjusting procedure at www.parktool.com starting at the beginning with proper height and alignment and loose cable.

First, ignore the indicator, grab the cable(to put tension on the system), shift down and make sure you are in the first position on the shifter.
Now shift the rear up to the biggest cog and adjust the front der. limit screw so there is a few mm clearance between the der gate and the chain.
Reset the cable, don't pull it to tight just put some tension on it and tighten up the binder nut. It is also a good idea to have the adjusting barrel on the shifter out a few turns to give you some room to play with the cable tension.
If this does not get you close then there is a good chance the der is either very poorly adjusted in relation to the chainrings, bent, or worn out.
The der should have about 2mm clearance over the largest chain ring and be more or less in line with it, maybe tip the back out slightly.