Not that I am aware of mate. I trade / invest as well, and also have a paypal account that I use. You're right, it would be nice, but not allowed, I believe it's due to SEC / Homeland Security Regulations. Which I can understand. Paypal
is international, and thus, could be used as a funneling channel by terrorists. I know - our account was hacked. Mastercard and Paypal called us, to let us know that they noticed payments were going to London, Toledo (A 'charity' that got busted for being a front), Liberia, Morocco, Chad, etc - all to various Islamic "charities". Needless to say, we were a bit torqued.
Sucks that something that could be so convenient for so many of us, is screwed up by the morons of the world.