When you create your hosted button on PayPal from the "Merchant Services" menu, you will be able to specify some advanced variables in "Step 3".

Add the following in the "Advanced Variables" field:

rm=2
return=http://www.yoursite.com/thank-you-page

Now, save and you will be able to copy the button code and paste it in your payment page.

The hosted button code will look similar to the following:

<form action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="hosted_button_id" value="7JK4AJCBQGJV6">
<input type="image" src="https://www.paypal.com/en_US/GB/i/btn/btn_buynowCC_LG.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online.">
<img alt="" border="0" src="https://www.paypal.com/en_GB/i/scr/pixel.gif" width="1" height="1">
</form>