You are using the fx versions of the plugins.
The fx versions have the noise source replaced with an external audio input source, hence the EXT label.
Just load up the regular version of the synth, in a midi track, and you will be ok;)
The function you are looking for is, as far as i know, not implemented in Synth Squad atm. Synth Squad has standard ADSR envelopes, what you are looking for is AHDSR, Attack-Hold-Decay-Sustain-Release. The hold stage is a definable time interval in wich the envelope is held fully open, regardless of...