I don't do this on purpose but when I pray, I tend to combine some of these postures from different religions. I usually sit down on my legs and hold out my hands in whichever way I feel like doing and pray. Sometimes I use the Christian prayer pose, sometimes I am in "namaste" pose and sometimes I keep my hands open like Muslims do. I think that intention is most important when reaching out to the divine. I like to think of religions as all one and the same. I do whatever I feel like doing at that moment.
I think postures are a uniting factor within religions. People feel good about themselves when they follow the same customs. I think traditions are very nice but I truly feel that these customs cannot be a barrier between beliefs or people.
I have visited temples, mosques and churches with my friends, even though I was not born into that tradition. Whichever house of prayer I am in, I like to learn about the prayer postures and customs there to show my respect to that belief, not to simply fit in.