Export the RFC destionations stored in table RFCDES into a flat file and then import them into the destination system.
In a SQL Server environment you can easily use BCP (Bulk Copy) to extract only those RFC definitions you want and then load them into a new system.
See the following example:
Export all RFC Type "3" from system "sapdev", database "DEV" into flat-file "rfc.txt" via BCP: c:>bcp "select * from DEV.dbo.RFCDES where RFCTYPE='3'" queryout rfc.txt -c -T -S sapdev
Please take caution when using this technique and please do so only at your own risk.
This was first published in October 2005