Question for film makers re camera. Can I use XL-1 footage in HD sequence?

My next documentary will eventually be getting funds but until then I am working guerilla style as there are things happening I have to shoot now. If I'm lucky I will get an old XL-1 to use now but once I get the funding will be buying an new HD camera in the 4 - 6 thousand range. This is a very important documentary which is already expected to hit Sundance and the rest of the good fest's. Once I get the budget together it's guaranteed international distribution from a pretty major Hollywood company. So I am panicking that even if I shoot the things going on now the footage won't fit in to the rest of the film once I have good equipment.

Any opinions on this? I've an opportunity to go to Vegas and then Mexico to shoot key interviews for the piece but as I said will be lucky to get it on an XL-1. Do you think this is better than nothing? As long as I shoot it 16:9 and light it properly will I be able to work with it?