Help How do you download an application directly onto the SD card?

[Talal5897]

Hey people,

I have only 50 MB of space left on my internal storage.
Sometimes when i try downloading an application, it starts downloading onto my phone first and then i have to transfer it onto my sd card.but since i have only 50 mb left, i cant download those applications because i get a message saying "insufficient storage available".
many other applications of mine have downloaded directly onto the sd card.
any advice on how to select the sd card as the preferential method of storage for downloads?

Thanks.