Well if the incident was created with a SRD (or you've set the incident to create a service request at each incident creation), you can access the SRD in the menu:

Advanced functions->View Service Request.

Same for the change:

Advanced functions->View Service Request.

Well at least for version 7.6.04.

Edit:

But I understand the feeling. My last customer asked to "unhide" the field SRDID in Incident which displays the Service Request ID, it's little "development".

the way i see this model somewhat works similar to Change-Task, Incident-Task, Problem-Task....if you see the way Task Management is used it actually acts as a Fulfillment Application isn't it? for the Parent Application(Incident, Change or Problem)....so the way how it works is the Parent Ticket will be fulfilled once all the Tasks are completed....this is called as dependent relation...

so If you go to Task you will see the Parent ID linked to that..but under relationship tab you would not find any relation of the Change, Incident or Problem....

ok about Relationship...tab of the Incident or Change or Problem what do we relate we relate another transactional object which is an independent transactional object...incident is not dependent on change it has its own life cycle...and change is not dependent on incident..it has its own life cycle...so independent relations are carried out under the relationship tab...

and the dependent relation we dont relate it we link it...so thats the reason you see a Change or an Incident is linked to the Task(which acts as the fulfillment application).....so if we apply this philosophy then Incident/Change acts as a fulfillment application for the Service Request...so there exists an dependent relation so we link it we dont relate it....