Hopefully, someone here with more experience will post as well, since I'm still new to this. I planted a Texas Star last year that got big enough to produce 2 viable suckers. I used a type of spade known as a sharpshooter, and carefully carved the suckers from the mother bulb of the parent plant. From what I understand, it is extremely important to make sure the suckers have at least a few roots of their own before trimming from the mother bulb.
I did this 5 months ago, potted up the 2 suckers, and both are still doing fine. There hasn't been a lot of growth, but at least they're still green and healthy. Hope this helps.

Thanks but my question was not about separating suckers.. but how to get the plant or force it to produce them... :)

hey i have noticed if you put it a pot a little bit too small they seem to produce suckers faster than in the ground!!!ST out!

Use a fertiliser like miracle grow or a lawn-start fertiliser to get more suckers.
The normal fertilisers for bananas will give only a larger plant, but less suckers. Normal use a fertiliser like 10-3-20 or 8-3-25, so large amount of kalium. To get more suckers, increase the ammount of nitrogen, so 15-3-20 or 20-3-25. (Notice the photassium concentrate does not alter.)
A Double Mahoi is from the triploïd acuminata group and should sucker a lot.
Look at the fertiliser you're using.
Simon

Hmmmm, I don't think it has anything to do with photassium, or kalium. More so it is genetics. Some pup more than others. If you stress the mother, it'll pup like crazy. Has momma flowered? If so cut her down, and she'll send out several pups. How tall is it now? Re-reading your post....1.5yrs old and no flower or pup?

it is potted... it sent out 2 pups last year.. no flower because last winter i left it outside, the mother died and only one pup survived

Give it some time, treat it well, and it'll pup when growth blasts off again in the spring. Plant it in rich, organic soil, in the full sun ample water, and feed monthly. Mine always take off, and really spread their roots in the ground. It's like they stay stalled for 2 to 4 weeks, then really, really take off. The 1st things I notice are much larger(length and width) leaves. I use 10-10-10, for vegatative growth, on all of mine and they do great. For flowering I switch to Citrus fertilizer 4-6-8 with minors or even better Avacado Fert. 10-4-10 with minors. The "Perfect" NPK(Nitrogen-Phosphorous-Potassium) ratio is said to be 6-1-8, but they THRIVE on just about anything I give them and will pup when nature tells them to, or if you damage/cut down momma. Also check out bananas.org, especially in the spring/summer, when everyone posts daily.
Good luck,
--Rick