To set the role up there will need to be a count type created within the LU_YOT_HEARING_ROLE table under YAP_SYS. This will need the count type of 'S' and the description of Solicitor.
Within the Hearing section, there is an attendee section within hearings. You can add an attendee that has the role of 'Solicitor' this is then picked up by AssetPlus.
If the telephone section needs populating then this Solicitor up as a person within Core+ under the People module, in this module you are able to add telephone numbers to the person. You would then add this person to the attendees section and select them with the role as solicitor. This will pull through the telephone number associated with this person.