How can you accomplish this configuration?

You want to ensure that all traffic arriving on interface fe-0/0/0.0 will be routed to next-hop 10.1.1.1, regardless of the more specific routes that might appear in the routing table.

How can you accomplish this configuration?

A.
Configure a default route with a next hop of 10.1.1.1 and configure the always-use flag for the route.

B.
Configure and apply a firewall filter that sends all traffic to a routing instance, configure a default route in that routing instance, and configure the router to install interface routes in that routing instance.

C.
Configure a routing policy that matches all traffic and sets the next hop to 10.1.1.1, and configure a RIB group to ensure that the routing policy can resolve the next hop to 10.1.1.1.

D.
Configure a firewall filter that matches all traffic and sets the next hop to 10.1.1.1, apply the firewall filter to a RIB group, and assign the fe-0/0/0.0 interface to that RIB group.

Explanation:
set routing-instance InstanceA routing-options static route x.x.x.x/x next-hop y.y.y.y

However, if the next-hop points to an interface which is not bound to the InstanceA routing-instance you the route is not going to become active.

This is typically why you would configure a rib-group and configure your interface-routes to be mirrored in the routing-instance and inet.0. Or if the interface is bound to inet.0 then you could simply create a default route inside the InstanceA routing-instance and point it to a next-table of inet.0.

Useful information:
http://www.juniper.net/techpubs/software/junos/junos95/swconfig-routing/id-10120848.html