Angelo,
You shouldn't have any problems with registration. Both ASCAP and BMI have pretty much the same easy requirements. The following is from the ASCAP website:
"To become a writer member, you must be the writer or co-writer of a musical composition or a song that has been:
-commercially recorded (CD, record, tape, etc.);
-or, performed publicly in any venue licensable by ASCAP (club, live concert, symphonic concert or recital venue, college or university, etc.);
-or, performed in any audio visual or electronic medium (film, television, radio, Internet, cable, pay-per-view, etc.);
-or, published and available for sale or rental."
-----------
I've been with BMI for 34 years and have never had a hitch. Whichever you choose, I suggest that you register as a songwriter AND a publisher. That gives you better control over your compositions.
Check out the "sitemaps" on both BMI.com and ASCAP.com. Both sites are very good and informative. Take a look at
http://www.nmpa.org/hfa.html for the Harry Fox Agency. They can handle the administrative, publishing stuff for you for a very small percentage.
Good luck,
Dave Nye
Yardley Music, BMI