Send packet w/out calling libnet_build_ethernet()

Hi, I am a beginner in libnet and I would like to do a very simple thing.
I have an ethernet packet that was previously captured by libpcap and I 
would like to send it back thru the wire without modifying it. What I 
did was to exctract the source, destination and type from the packet and 
call libnet_build_ethernet() with these parameters. It worked well but I 
would be pleased if someone could tell me a way to do it without having 
to extract and insert back the ethernet header.

Thanks in advance,
Fabio D.

PS.: I am doing this under linux.