1.The problem is that most of our sources for reference are Western / Christian. That is why we are mostly left in the dark. The Palestinian Christian writer Eduard Said opened our eyes to reality. For instance, not much was known about al Andalusia till Tariq Ali brought that subject to light. In recent times translations work has begun from Arabic and Persian into various languages including Bengali and Urdu.
2. We now know that The Message had arrived in our shores during the life-time of the holy prophet PBUH. Sahabi Abu Waqqas, his uncle was sent to convey the divine Message to the Araba community living along the coasts in the maritime silk road stretching from Canton to Aden. The Sahabi stayed in Arakan, Chittagong and Sylhet region for eight years. His journey had begun even before the Hijrat ( around 621 AD). After his work here he went on to his final destination, China. On a visit to Guangzhou you can see the green colored mosque he had built - one of the oldest in Islam. I am blessed that I could offer my prayers thee during a visit. The local Chinese Muslims call it the Mosque of Our Ancestor, and his burial place nearby is called the Mausoleum of Our Ancestor.
3. On the other-hand, the first physical contact of Islam with the Indus valley was in 723 AD. But Qasim was withdrawn quickly before he could involve himself in the work of Dawa't. The real entry of Islam into present day Pakistan was in 903 AD when Amir Sabuktagin took Peshawar in 977 AD.
4. The Message arrived to us fresh, direct, in-tempered and uninfluenced. It arrived in the Indus Valley late with the influence of time on it. Moreover, powerful cultures like Persian, Byzantine and Assyrian had left their mark as a result. Therefore, we in BD have no sects, although for official purpose we say we are Sunni. But in the Indus Valley the situation is different. In Pakistan society, Islam is yet to get totally free from the influence of tribalism and cast. We in BD are proud that much like the Eastern Mussalmans, we have preserved and nurtured the Message exactly as we had received - in spite of all trials and tribulations.