Have had this exact problem myself a while back.
For local flights ie. landings training area:
I hereby certify that I have given Mr./ Mrs. ............... the flight training mentioned in 14 CFR part 61.87(o), and find him/ her competent to conduct safe night solo flights to and from (insert airports in the vicinity or training area here) and (base airport)
Signed.... yadda yadda exp. yadda yadda
This endorsement is valid for 90 days, in order to endorse the students logbook you should (have to!) conduct training at night to include navigation to and from the practice area, navigation to and from any foreign airports for landing practice including joining the traffic pattern. Landings at night.
This brings up the next issue discussed.
Since the student is flying on a validated license without nightflying privileges, you should (have to!) endorse the presolo type as you would a student pilot ie. the make and model endorsement.
Additional endorsement for cross-country flights at night is also type-specific. (61.93)
So...
2 endorsements for solo night flights
3 include cross country
Regards
MAS