Pass a URI as a PgAdmin parameter

I can connect to Heroku with psql passing a URI:

psql postgres://user:password@ec2-54-243-xxx-xxx.compute-1.amazonaws.com:5432/d7xkxididkdi

I want to do the same with PgAdmin:

pgadmin3 -qc postgres://user:password@ec2-54-243-xxx-xxx.compute-1.amazonaws.com:5432/d7xkxididkdi

but I get the error message:

Unknown token in connection string: <the passed string>

Is it possible to pass a URI as a PgAdmin parameter?