This paper presents the modules that comprise a sign generation tool for Greek Sign Language (GSL). The tool combines Natural Language (NL) knowledge with avatar technology in order to allow for unrestricted generation of sign utterances. The NL knowledge of the system is exploited in the context of typical NLP procedures, which involve syntactic parsing of linguistic strings as well as structure and lexicon mapping according to standard Machine Translation (MT) practices. The coding on linguistic strings which are relevant to GSL, provide instructions for the motion of a Virtual Reality Modeling Language (VRML) signer, that performs the corresponding sign streams. Dynamic synthesis of GSL linguistic units, is achieved by combining syntactic rules of the language with a lexicon that contains lemmas coded as to features of GSL phonology. This approach, although sublanguage oriented as regards our current implementation, allows for unrestricted conversion capacity of written Greek to GSL, which is an essential prerequisite for access to e-content by the community of native GSL signers.