How simulate trick htc wildfire charger (get max current)
The way to indicate phones that they are connected to the wall charger is by shorting data pins as you have already found out.

Your problem might be different, some times you cannot achieve full charger current because of the voltage drop along the cable. If the voltage at the phone's input is not high enough (that value will vary from phone to phone, but it should definitely be higher than 4.3V), the phone will start limiting it's current draw.

You can check this by measuring the voltage at the phone during charging, if you can reach some measurement point. Or you can also measure the cable's resistance and do the math. To measure that resistance I recommend that you make 1A pass through that cable and measure voltage drop.