scscp2: STS Unavailable

scscp2 defines the following Names, but STS signatures are not currently available.

• store_session
• store_persistent
• retrieve
• unbind
• get_allowed_heads
• is_allowed_head
• get_transient_cd
• get_signature
• get_service_description
• signature
• service_description
• symbol_set
• symbol_set_all
• no_such_transient_cd