Create a virtual gift certificate and it will be available for use immediately...just log into your Dish Network account and then have your mom use the certificate number.
On a side note, good luck getting credit for your Club Dish referral. I've referred six (6), but have only received credit for one (1). I suggest dumping the Club Dish idea and have your mom call the DishStore.
Have you pursued the credits with Dish? I got a response from a Mark Duffy at firstname.lastname@example.org and he made sure I was credited for a previous install and it actually shows as a "reward" in my dish club history. I can't believe they would be so low as to not give you credit for getting new business! That would totally suck.
The folks at E* know me very well...even spoke to the above individual a couple of time regarding other issues. To be fair, I later found out two of the individuals were former E* customer (although it was more than 3 years for each), one forgot to mention the certificate when placing his order, and the other two went through a retailer who used their own certificate number. The ClubDish referrals are pretty low on the priority list...and I know a number of people who have had problems receiving credit. I've probably had 6-8 referrals for Verizon Wireless and never had a problem receiving my $25 credit.