The entire handbook is now available on the web by going to www.nicaraguansignlanguageprojects.org and downloading the desired link (under "projects now and future" section.) The links are divided into the grammar and syntax sections (English or Spanish versions) and 18 vocabulary topics: adjetivos opuestos (opposite adjectives), alimento (food), animals (animals), calendario y la hora (calendar and time), ciudad y campo (city and country), clima (weather), colores (color), en la casa (in the house), escuela (school), familia (family), geografia (geography), medico (medical), negacion y afirmacion (negation and affirmation), sentiminetos (sentiments), transporte (transportation), verbos (verbs)
The only sections not available are the acknowledgements page and indexes.
There are about 875 sign entries (with SW transcriptions) -- a mere sampling, of course. The grammar & syntax section is far from exhaustive but, I hope, will be helpful to serious students of this or really any signed language.